Franklin creates a pocket universe for his parents and others after their battle with Onslaught. The books were done by post Image creation Lee & Liefield. It did not go well and everyone came back.
Also this was around the time Marvel money issues and buying (destroying) Ultraverse universe was also happening.
I suspect this is more allowing testing of new creative teams and filling in the summer to allow time to catch up on stuff. Along with plan whatever event for FF since November 2021 is their 60th anniversary.