Wrong assessments of individual experiences
Here the asker potentially wrongly assessed something that happened to them – as opposed to general facts. For example:
Assertion: The student I supervise does not take my criticism seriously.
Assertion: My paper was cited for some claim it did not make.
In these cases, we almost always lack relevant information (or it would be off-topic) and cannot make a judgement. The asker should know better than we do, and they are responsible to ensure that such an assertion is correct. Therefore frame challenges about such situations are usually not appropriate.
However, there are some exceptions, where a short and tactful caveat is appropriate:
The misconception is common and applies to many people in a similar situation, e.g.:
Assertion: The referee did not thoroughly review my paper, as they misunderstood the key concept.
Caveat: Before proceeding please consider that you are very familiar with your work and thus may not have noticed shortcomings in your explanations.
The asker describes in detail how they arrived at an assertion and this makes it seem unlikely that they are correct. For example:
Assertion: My professor is not satisfied with my work, because X, Y, and Z.
Caveat: What you describe are normal activities for a supervisor.
Just by your report I would not assume that your professor is dissatisfied.
If the asker’s judgement should be incorrect, it may have severe consequences:
Assertion: My professor asked me to fudge some data by applying X.
Caveat: Please be aware that this is a serious accusation. I am not saying you are wrong, but before escalating this, please consider consulting with an expert whether applying X is really inappropriate in this situation.
In all such cases, such a caveat should not be much longer than the asker’s description of the assertion and respect the asker’s assessment instead of directly denying it.
Mind that this does not apply to questions asking us to evaluate a situation, e.g.:
My professor does X, Y, and Z. Is this normal? Does this mean that she is not satisfied with my work?
Sexism, racism, discrimination, and other traumatic events
A delicate subcategory is when the asker experienced sexism, racism, discrimination, or similar behaviour, usually towards themselves. Such events are often traumatic and denying what happened may easily add to the trauma. Moreover, we almost certainly don’t know all the details (context, tone, gestures) and thus cannot judge the situation.
In this case, the above exceptions do not apply: We can assume that the asker has already considered alternative interpretations of events and is aware of the severity of the respective accusations. At best, you may very tactfully ask for further details or assess the details if relevant for the question, e.g.:
I am sorry for your experience. To better answer your question, can you please  your question to tell us whether you have any evidence of this? I understand if you do not want to go into the details; it suffices to know how much evidence you roughly have.