404 on repository revision access using git
1. Commit and push a new revision to your git repository
2. Load the url pointing to that commit in your browser: http://.../<project>/repository/revisions/<hashstart>. You will get a 404.
3. Load the repository overview page http://.../<project>/repository/
4. Load the previous url again. Everything works now.
Thus Redmine only learns about new revisions ones you loaded the overview page of the repository before. Fix sounds simple. Add the call to update the repository to the revision access, too.