Both the pelvis and feet are very messed up. I’ve tried retargetting the mesh but with no luck. There seems to be no solution online as to why this happens. I use auto-rig pro in blender to rig it. When i apply the mesh to the actual base mesh
It works just fine, but of course it means i cant use ragdolls etc etc etc…
using the auto-rigger is by no means perfect always. sometimes you still need to weight paint a character to make things more smooth and work as it should
It’s not due to auto-rigger, I tried on my side with Mixamo, Accurig and also a hand made rig matching UE mannequin, also a Market Asset already rig to UE mannequin. If it’s smaller then “AnimMan” the ALS Character, it will stretch to match the bone.
You can partially fix it by changing the retargeting options but it mess some of the Hand IK animation like holding weapon / object.
Because ALS’ procedural anims use the UE skeleton for reference. It’s expected to run into issues such as stretching if you do not scale your character accordingly. It is fixable, however you would have to manually adjust IK’s and other bone transformations in the animBP.