Try to figure out if a particular morph is causing it. Try different morphs. If built-in morphs do that, then the model is wrong. The rigging might be FUBAR.
I don't remember any finger bend fixes, but as a last straw you could try to merge/separate your current morphs, if you are just interested in the end result and don't need to refine further single morphs:
-- Content: - Morph Merge and split script files. -- Description: - An edit to the original Morph Merge and split by @ceq3 , This edit adds the following features: - Split hands feature. - Split feet feature. - Splitting hands & feet & head with...
hub.virtamate.com
Check the option for splitting hands and feet, export everything. Then start with a default morph base, reload custom morphs and activate every exported morph but the hands. If the hands had specific problem free morphs you want to keep, you would need to dial them in again.