"He might have said it in fun" I don't see anything wrong with this formulation. Given the context of your original post I would not have taken it to mean a specific occasion. In fact your revised version here is better than the original.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Avangi it does seem strange when you think about it.Not to me. A little old-fashioned, maybe, but I like it.
AvangiAny guidance on this?? << He might say it in fun. >>A (fairly rare) case of might as the past tense of may, I'd say (in the intended reading).