I first encountered this in my GA match yesterday. I thought it was new, but apparently it has been happening since July.
CG had posted this since 12 July, but cleverly under EA Answers instead of this forum. In my opinion, I don't think there is as much traffic there as here, so few people know the extent of the problem.
They had lumped all the bugs together, which confuses issues.
Subsequently they posted a separate bug report on 29 July, now calling it "Ability Icons Disappearing". In their post, they acknowledge it has been going on for 1 month but they haven't gotten a consistent reproduction and are still investigating. This bug seems to be affecting not only GA, but also TB, arena and fleets (although most screen shots show GA and TB).
There are 295 posts in the first Discussion, and 50 posts in the second Discussion. People are continuing to post in both from the most recent GA matches with similar problems, and it seems that we are confused as to which Discussion / Bug Report we should post our issues into. As evidenced, after over 1 month, CG/EA has not been able to address the problem, they are continuing to occur, people are confused and unsure where to post, and yet a new round of GAC has continued to be pushed out.
I have 2 big issues with the way this is handled:
1. Why "hide" it under EA Answers HQ, instead of having a Megathread here that continues to accumulate feedback? Are they afraid of the visibility that this bug in the game would produce?
2. Grand Arena is supposed to be the "pinnacle" of the game where you fight with other players for top spot. There are a lot of players, whales or otherwise, who invest a lot of time and effort (and money) into this, hoping to win GA rounds and get into Kyber. Having a bug that messes up with your matches, and puts you in the 2nd or 3rd tier of your GA match-up instead of 1st, obviously goes against what the GA matches were meant for - that the best players come out top. Now, it depends on whether you are unlucky enough to have your battle hung mid-game.
CG should suspend GAC until this is sorted out. And be frank with it and state it here in forums / announcements, that the bugs need to be sorted out to provide the experience that GAC was intended to provide. Otherwise GAC is a farce.