Something changed between SubGit 3.3.10 and 3.3.11 that results in hooks/post-receive not being called when installed into a GitLab 13.10.1 hashed repository.
To verify, I uninstalled 3.3.11, reinstalled 3.3.10, ran “subgit install …” on one of the affected repositories to roll back to 3.3.10, then pushed a commit to the sync’d Subversion repository. The post-receive hook is called as expected.
The problem happens regardless of the states of “gitlab.triggerSvnPostReceive” or “svn.triggerSvnPostReceive”.
As an aside, up to this point I’ve successfully used the post-receive hook to ensure merge requests are updated properly, and to work around the issue reported here: