Yeah, I was standing as far as possible. I was checking to see multiple spell effects in the air at the same time and I did, and tried to look for MSBT (not too accurate, I'm afraid) that the damage was hitting at when the spell was landing and it seemed to be true as well.
I don't know if this is a recent thing or tied to certain spells or not, but in my guilds Ragnaros video, there are 2 or even 3 wraths in the air simultaneously.
Yeah, strangely I never felt the "one in flight" mechanic enough to even know it really existed until somewhat recently. It's rather annoying, especially if Unerring Vision goes live in its current state. Will just have to try and get better positioning as close to the bosses as possible, I suppose.