The git hooks have following quirks:
1. The prepare-msg (I believe) hook adds a space at the end of the PHPBB3-number line, which makes the message be rejected unless the space is removed manually.
2. A newline after PHPBB3-number is not accepted by the message validation hook. Git does not care about such newlines, in fact it even adds them when ammending.
3. Empty commit messages trigger a really awkward validation message. Instead, if the commit message is empty (after removal of comments) it should just be handed on to git, which will then handle it gracefully.
It would be nice if the message rejection were a bit less strict and a bit more helpful in general.