Unexpected cat-file --batch-check output

I'm working with some users trying to reconcile an odd mismatch observed in some Git output.

Running an ls-tree for a branch and path, limited to a single pattern within, shows this: /usr/bin/git ls-tree -z refs/heads/develop:path/to/parent – file 100644 blob 4c8d566ed80a1554a059b97f7cd533a55bbd2ea8 file

If we then run cat-file --batch-check, though, we see this: echo 'refs/heads/develop refs/heads/develop:path/to/parent/file' | /usr/bin/git cat-file --batch-check 28a05ce2e3079afcb32e4f1777b42971d7933a91 commit 259 cc10f4b278086325aab2f95df97c807c7c6cd75e commit 330

There's a newline after the branch name, inside the single quotes, followed by the same branch name plus the full path. In this output, it comes back as a commit, though. Both commands were run with refs/heads/develop at the same commit. I've checked for a .gitmodules file and while they _do_ have submodules, they're at different, non-intersecting paths to the one in question here.

I can't share the actual repository (I don't have access to it myself), but I'm hoping someone might have some ideas. I've never seen this sort of mismatch before; for every path in the repositories I do have access to that I've tried this for, the cat-file --batch-check always shows "commit" (or "tag") for the ref, and then "blob" for the ref+path. Submodules were the only thing I could think of, but that doesn't appear to be the case. Could it be a subtree instead? How would I check?

Thanks in advance for any ideas; I appreciate any help. Bryan Turner