1) Please mention which specific cleanup tool triggered this error.
2) Please mention how the error displayed. Was it for example a little warning attached to the top of the main cleanup tool results, below the main results, a part of the results, reported tangentially (e.g. in a separate error email), or a big error that stopped the process in it's tracks?
I believe this would be the broken URL check, and only happen if you had deleted a topic you linked to somewhere. It would have happened in an error message notification, not on the screen itself. As that is a likely thing to happen, I will disable this error message for topics. I will also make it more clear, as it is truncating the full page-link which should really of referenced the topic ID involved.
I did several at once, so not sure, and yes it was a system email. I don't tend to link to topics at all, only pages, so I think we can rule that out. I will see if I can trigger it again and let you know more details.
Something was definitely linking to a topic. It could have been something very casual, such as just a topic link pasted into a forum post somewhere. There is no actual bug here, so no need to keep us informed.
1) Please mention which specific cleanup tool triggered this error.
2) Please mention how the error displayed. Was it for example a little warning attached to the top of the main cleanup tool results, below the main results, a part of the results, reported tangentially (e.g. in a separate error email), or a big error that stopped the process in it's tracks?