While working on a test case for, I found that aggregator category blocks do not render at all because of changes in . The fix is simple, hopefully and I will be posting it in a comment.
I am not sure if this qualifies as a critical or major bug. Given that one of the system is not at all working and there is no workaround, I think it is at least major. It is quite surprising that it was not spotted earlier. I guess there are no tests for this. I am working on a test forwhich will test this function too. Maybe this patch could go in without the test case. Thoughts, please?