That happened in September 2020. Thunder Rosa and Ivelisse had beef because in that match, Ivelisse (the girl in the red) was no selling Thunder Rosa's strikes and botched the finisher.
Notice in the beginning of the video how she would get hit with an elbow to the head, instead of acting like she got hit, Ivelisse would just start fixing her hair. So after a bit of that, Thunder Rosa started hitting her for real.
And then she botched Thunder Rosa's finisher. TR's driver is supposed to look like this:
Ivelisse wouldn't move her head, so Thunder Rosa ended up doing a Tombstone piledriver instead.
This video was only brought back up because Ivelisse was released by AEW this week.
Apparently, she had beef with AEW's agents at some point after that fight. On top of that, they decided to keep her and Thunder Rosa apart, so they kept Thunder Rosa on Dynamite, and Ivelisse on Dark. Ivelisse claimed favoritism, but really Thunder Rosa was just better than her (as we saw in her hardcore match vs. Britt Baker).
Ivelisse was already an NXT reject and has a bad reputation. Thunder Rosa was the NWA champion.
So no, that's not an indictment on AEW's women division, that was on Ivelisse acting up because she wasn't getting her way or whatever.