been gone, what changed with the gearscore battlegroups?

hello i came back after having a break from wow, before i played full starter relentless geared chars on blackrock and got with no shadowmourne full wrath geareds in any bgs but now i get it 100% of the time on all chars and i tried making a brand new and q bg and got with smourne full geareds, can someone inform me of what changed? is the only way to avoid full wrath's now to make a seasonal furious gear one and play those bgs in that battlegroup? annoying fixing like 6 new chars with everything..

There were changes made to facilitate Frostmourne players. It will go back to normal after their season ends.

I'd really like to know when the option to opt in to battle group 2 will return tried making a new toon today on blackrock and noticed I didn't have the option I honestly don't wanna play with Shadowmourne players in battle group 1.