It seems that cloth simulation doesn't work correctly on 4.20 if Compute Skin Cache is ON.
We can easily repro it with Content Example
[Link Removed]
Is this by design?
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-62951 in the post.
| 4 | 
| Component | UE - Simulation - Physics - Character | 
|---|---|
| Affects Versions | 4.20 | 
| Target Fix | 4.21 | 
| Created | Aug 16, 2018 | 
|---|---|
| Resolved | Oct 8, 2018 | 
| Updated | Oct 29, 2018 |