Apparently, Gizelle and Karen are cool now. They are going to go at it early in the season, but get better.
I predicted this. This is something Erica Dinero was talking about. What made most of the HW shows good was a shared history with at least most of the cast.
Nene, Sheree, and Kim all knew each other for years.
Ramona, Sonya, LuAnn, and Dorinda knew each other for decades.
LVP, Kyle, and Adrienne knew each other for years.
Most of the original NJ cast were friends for years.
Gizelle, Robyn, and Karen were friends for years.
Having a history and friendship that spans years and decades before the show means you have something to fall back on when you have a falling out. Generally speaking, you can get over it and agree to be friends again even after you argue and say horrible things to each other.
None of the Atlanta women have a friendship older than their presence on the show. They only know each other through the show. They have nothing keeping them from cutting each other off after they beef. They have no history together beyond the show. That's one reason why the chemistry is off.