The other day, I was learning with a chavrusa in shul after maariv. The people sitting in front of us and behind us held a conversation kind of over our heads, in which one asked the other where his chavrusa was, and was told that he was at a siyum. However, the siyum was not fleishig, because he had asked the rabbi (a widely respected Orthodox rabbi and competent posek) and the rabbi told him that he should not have meat by that siyum.
When my chavrusa broke into the conversation to ask why that might be, they got very defensive and pretty much said "it's none of your business." (so then why have that conversation in public...?)
Why might someone be allowed to make a siyum during the Nine Days, but not be allowed to have meat by the siyum? Bonus brownie points if your explanation also covers why this might be a sensitive topic.