The user needs to avoid operations that generate NaNs, as different hardware has different levels of support and/or behavior regarding NaNs.
NaN (Not a Number) is handled different when clamped on Windows and Android/iOS. If you clamp a NaN (Acheived by -3 ^ 0.2 in the reproduction project) from 0.0 to 1.0 and then print the result, you'll get a 0.0 on Windows. If you do the same on Android and iOS, you'll get 1.0.
This also occurs in 4.16
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-51441 in the post.