Comet quality. "Repeat" doesn't work?

I have q20 comet, and I've been testing it for several minute - casting it non-stop and trying to see if it repeats or not.
I couldn't see it repeat a single time.

Now here's the question - how does "repeat" even looks like? Is it like spell echo? If so, then it's bugged, because I don't believe that 4 minutes of casting it non-stop wouldn't result in a single repeat.

Or is the repeated spell overlaps with the original? If so.. Maybe it shouldn't be like that? Because I can't even tell if it's working or not.

Another day of playing, still haven't seen "repeat" to occur even once.

I'm convinced that it simply doesn't work.

Bumping this. Also noticed that the comet never repeats, whatever that means.

Also reporting quality on Comet is not working at all.

Same :\ Never seen a single repeat, standing still casting a bunch and no dice. I have it linked with Unleash support so I removed that and same, 40 some casts and no repeats, seems it is indeed just broke.