When I look to the close review queue I sometimes find that other voters have given a different reason to close from the one I has eventually decided on. Sometimes though I was only 60:40 in favour of my decision over theirs. I see from the documentation that it is just the overall count of 5 which matters but would it be more helpful to questioners if I went with the majority? I am not proposing to vote for something I definitely disagree obviously, that would be unhelpful and dubious behaviour.
I agree that this is common.
I don't find it especially troubling on the whole. If a question is unacceptable on any ground, it doesn't belong. If you throw something out, it is secondary why you do.
At the same time, good (concise, precise, informative) feedback will tell the OP what was wrong (and help them to do it less often in the future). In addition, that feedback may remind others of the boundaries we have (and, more optimistically, of where they tend to be drawn).
But the mix of reasons can imply some inconsistency. Whether the inconsistency is problematic is a deeper question.
Example 1: a question is, according to different voters, too broad and unclear. This can often happen with poor questions. Anything close to How should I analyse my data? can be a poor question on both grounds: it is too general without more specifics on the problem and it can be unclear what kind of answer is expected.
Example 2: a question is, according to different voters, too much focused on code in some software and deserves migration to Stack Overflow. This is a common clash. Sometimes a visceral "No! this is really a programming question" can disagree with a recommendation to migrate. The need here is to look closely to see if at the heart of the question there is a reproducible code example that would be acceptable on Stack Overflow. That's a tough call unless you have some familiarity with what does and does not go down well there.
In general, just vote the way you think; (weighted) majority rules as to what reason it closes under. If you think that a post could be closed under several different close reasons, post a comment explaining the problems for the benefit of the OP.