receive.denyCurrentBranch=updateInstead won't update the repo

I'm using Git to push-to-checkout a website.

The receive.denyCurrentBranch=updateInstead option (set on the server
repo), according to the docs, should allow the push and do a checkout
on the worktree if it's clean, or just refuse the push if the worktree
isn't clean. Instead, for me it allows the push, but doesn't update
the worktree - I have to `git checkout -f` on the remote shell after
each push, even though the worktree is clean.

Note: The `push-to-checkout` hook doesn't seem to run, either, even
though it's in the .git/hooks/push-to-checkout file, with +x rights as
needed. I made it output some lines and exit with code 1, so it should
abort after producing the output - and yet the pushes come through.
Other hooks, like `update`, work fine and can abort if they exit 1.

Setup:

My client is 2.31.0.windows.1 (TortoiseGit)
Server’s git is 2.39.1.
My remote is set as ssh://user@hostname.com/path.

Please advise what I can do to investigate further.

-- 
Adam "Sinus" Skawiński