Same problem for me.
I did claim them a while ago, and now I can add them to a project through the epic game launcher, but there are no access through fab for someone who has not added the assets prior to the fab migration.
Being a teacher, I wanted my students to use the same assets as I do for my exercises, but because of that it is not possible (or rather, pretty cumbersome to do). Any idea when they would be available again?