Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2080 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 451.67
Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: rB0330d1af29c0
I have not seen hair behave this way before. For this example file, I have simply used the default hair dynamics settings. I have a bake in the file attached, and you can try bake yourself to replicate the issue. The hair will fly all over the place, it is not colliding with anything and I cannot figure out what is causing the issue. It was recommended by a developer that I post the issue here for others to have a look, many thanks.