If a Tactics Trainer puzzle does not have a "Report Problem" link then it has already been confirmed as correct. If Rb4 on the last move then Black can play Rh5 and it will no longer be a checkmate. In the main line of the solution a checkmate can be forced by White.

Patzer24: If a Tactics Trainer puzzle does not have a "Report Problem" link then it has already been confirmed as correct.

How about this one (problem ID # 0041054)? Isn't requesting White's last move unnecessary?

This really frustrates me. Just because you reviewed the problem does not make it immune to all the possible ways it could be wrong. I have seen a number of problems that clearly needed fixing with no Report Problem link.

One thing I do not understand is why you don't ask the user to explain what the difficulty is. I usually leave a comment under the problem explaining my objection but I'm sure many people don't bother.

I really think that if I take the time to report a problem and leave a comment the least you can do is respond in the comments explaining how the problem is being fixed or why it doesn't need to be fixed. It bugs me when I report a problem and absolutely nothing visible ever happens. It's also very confusing when someone does fix a problem without leaving a comment, so that all the previous comments no longer make any sense.