This is odd.
Alright, I may have figured out something to test, but I don't know how to prove it.
I'm seeing what you're seeing, but only because the wave *appeared* in stages on my screen instead of all at once.
I think the Riot IIs got on the same 'timer' and were firing simultaneously. I have no idea how that happened, but I'm now seeing exactly what you were.
This is VERY strange. I don't see the 2 second paralyzes anymore, either.
Attached is an original screenshot of what I *was* seeing. Note the 2 second paralyze on the bomber.