I think its always been broken. Only 1v1s can go.
Entire Match Play needs to be re-done. TBH , I've made posts about it before. Unfortunately it's just trying to do too much in one arena. Need to separate AI fights from the dueling arena and just make It it's own arena and allow Match Play to be free fight with airspawns while fixing the 2v2+ modes. Also, the scoring system needs to be removed as well.
Would make it 100x better. But not sure how much work it would actually take.