I am making an attempt to know how the Feywild time warp impact works. (Word that use of want spells, or some other impact that alters the time warp impact for under explicit creatures, are out of scope of this evaluation.)
Terminology
To determine the state of affairs, suppose that at a given time, an adventurer within the Materials Airplane stands close to a portal to the Feywild, takes two synchronized clocks each set to zero, and places certainly one of them into the Feywild.
Suppose clocks can rely days and “time zero” is the time the clocks had been synchronized. We name the clock within the Materials Airplane the Mclock and the clock within the Feywild the Fclock. So we write e.g.:
M/x = the time that the Mclock reads x days
F/y = the time that the Fclock reads y days
There are two fashions that appear to be steered by the textual content, neither of which makes full sense.
The Monotonic Operate Mannequin
The textual content says that point passes at completely different charges within the Feywild and Materials Airplane, and that this ratio of time charges can change. Thus, one can take into account what would occur if somebody was standing by the Mclock, trying into the Feywild on the Fclock, and repeatedly recording the time proven by the Fclock e.g. each second on the Mclock. Since time doesn’t go backward on both aircraft (simply ahead at completely different charges) this might yield a monotonically rising operate f(x) that offers the time on the Fclock when the Mclock reads x. (And f(x) would presumably be generated by some random course of – no matter makes the time run at completely different charges)
In that case a consumer who left the Materials Airplane at time M/x would arrive within the Feywild at time F/f(x). Equally, a consumer who left the Feywild at time F/y would arrive within the Materials Airplane at time M/g(x) the place g() is the inverse of f().
This interpretation leaves it unambiguous as to when an individual leaving at any given time will find yourself. It additionally makes it inconceivable to ship messages again in time (i.e. from F/t to F/w, or M/t to M/w, the place w < t) and so doesn’t permit for time paradoxes. Nonetheless, it isn’t in step with the way in which the impact is described within the guidelines:

First, take into account the case the place Alice goes from the Materials Airplane to the Feywild at time M/0 (and thus arrive at time F/0), then at time F/2 Alice jumps again to the Materials Airplane. The likelihood that Alice will arrive again at M/730 is 0.05 (if she rolls a 20 – days into years – on the time warp die). Nonetheless, suppose as an alternative that at time F/1 she jumped again to the Materials Airplane for a really brief time (for instance a fraction of a second) and again to the Feywild, then stays within the Feywild till time F/2. Then that is two separate journeys and to ensure that Alice to reach at M/730, she must roll a 20 each instances, a a lot decrease likelihood. However this is not sensible since f() is a world operate that simply represents which Mclock instances hook up with which Fclock instances, and would not rely in any respect on when Alice made her jumps.

Thus, if this had been the case then both (a) the distribution of the ratio [Material Plane time interval] / [Feywild time interval] given a randomly chosen interval in Feywild time [w, t] (that’s, (g(t)g(w)) / (tw)) would rely on the size of the interval. Equally, this ratio for a given journey can be correlated with the ratio for different journeys that befell together with the identical instances. However none of that is said to occur within the guidelines.

An fascinating idea on this case is that the distribution of time ratios would rely on which aircraft you began from. As an example, suppose that f(x) was piecewise linear over 0 < x < 500, the place f(0)=0, f(1)=400, and f(500)=500. Then, an observer within the Materials Airplane who selects a random time uniformly distributed on the Mclock to cross over would virtually actually (99.8% probability) discover themselves at a time the place the Feywild ran quicker (100 Feywild days = 499 Materials Airplane days). Nonetheless, somebody from the Feywild who chosen a random time uniformly distributed on the Fclock to cross over would have an 80% probability of choosing a time when the Materials Airplane ran quicker (1 Materials Airplane day = 400 Feywild days)
The GuidelinesAsWritten Mannequin
On condition that the monotonic operate mannequin seems to contradict the principles, one can as an alternative work the wrong way, and take into account the principles as written, the place the time charges are rolled for every touring occasion individually.
Suppose now that Alice and Bob, members of separate events, each undergo the portal at time M/Zero and arrive at time F/0. Then Alice stays till F/1 and goes again, and rolls a “no change” on the die so arrives again at M/1. Bob stays till F/1440 and rolls a “days into minutes” outcome, so arrives again at M/1.
The query right here is: If Charlie, who was not concerned in both earlier journey, goes by way of the portal at M/1, when on the Fclock will he find yourself?
The foundations don’t specify, however plainly any reply beneath F/1440 will result in a scenario the place backwardintime communication is feasible: Bob takes the message from F/1440 again to M/1 and provides it to Charlie to take again to a earlier Fclock time.
One might keep away from backwardintime paradoxes by saying that if you go away the Materials Airplane at time M/x you all the time arrive at time F/(1440*x), after which if you go away the aircraft at time F/(1440*x + y) then you definately arrive again at M/(x + y*z) the place z is the rolled ratio. However this might imply that if I used to be within the Feywild for a couple of days, and popped again into the Materials Airplane for a couple of seconds, I’d virtually all the time get again within the Feywild many Feywildyears later, which does not make sense.
It’s notable that the principles say that the time warp impact solely utilized in a single route (when getting back from the Feywild) Thus, one might interpret this one of many following methods:

Once you go from the Materials Airplane at M/x to the Feywild, you all the time find yourself at F/x. This permits for sending data again in Mclock time in addition to Fclock time (e.g. have Charlie go from M/10 to F/10, give the knowledge to Alice, then let Alice hold onto it to deliver it again from F/24 to M/1). Word that this requires preplanning to ship Alice in earlier in addition to having to hope for luck that she rolls a outcome that sends her again.

If I return from the Feywild and wait n days within the Materials Airplane, once I return to the Feywild I’ll all the time be n Feywilddays after I left Feywild. In different phrases, if I return from F/y to M/x, then if I am going again by way of the portal at M/x+n I’ll arrive at F/y+n. Word that this successfully signifies that every traveler (or group of vacationers) has a separate “time offset” – within the above instance, after Alice and Bob’s journeys, if Alice had been to return by way of at M/5 she would arrive at F/5, but when Bob had been to return by way of at M/5 he would arrive at F/28. On this case, if one had a community of a number of people who made a number of journeys to generate completely different offsets, they may ship messages again in Mclock time by having somebody with a smaller offset go away a message within the Feywild and somebody with a bigger offset deliver it again.
Is there any RAW or statements from the designers to help which of those is the meant interpretation?
Is there any official D+D fiction or setting materials that describes the time warp impact in additional element?