Reproduced 3/3 times, issue also occurs in //UE5/Release-5.0 - CL 20979098 Binary. Confirmed NOT a Regression.
Simulation appears to work fine when scaled by 10, but any higher and it starts to misbehave.
Actual Result: Cloth will bunch in on itself, vertices float in all different directions, etc.
Expected Result: Cloth simulation should be consistent regardless of scale.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-173312 in the post.