additionally, I found is that clearml==1.0.5 package is able to find these partial changes, newer versions find nothing at all, maybe it's because it's always comparing against remote

Hmm it was always from remote...
it is actually doing the following:
git rev-parse --abbrev-ref --symbolic-full-name @{u}Then with the branch name output,
git diff --submodule=diff <add_branch_name_here>