Bot acting in a way that confuses me 

Mr.Z-bot just reported  at AIV because he "Tripped filter 139 (details)."  Not sure how this is a problem, since the user wasn't able to do anything of vandalism or otherwise problematic, because he was prevented from so doing by the filter.  Is there a good reason why this would be reported?  Not challenging you: I just don't know what this is, so I'd like to understand.