#138435 was an attempt to fix the issue in #138168 where the Smooth Operator modifies locked vertex groups. Unfortunately, the fix actually changed some already-correct code to be incorrect to compensate for the buggy code in the Smooth Operator. This reverts that fix and applies a correct fix, which is to exclude locked vertex groups in the Smooth Operator's code itself. Pull Request: https://projects.blender.org/blender/blender/pulls/141093