I have the exact same problem. I'm stuck in 'loading contents' if the prim (root or child, doesnt matter) has more than one item inside.
I have cleared my cache, bug still there.
I flushed my temp files, bug still there.
I tried another account, bug still there.
I installed the official SL viewer fresh, bug still there.
I tried several different regions, bug still there.
I have reset my router, bug still there.
I don't use a VPN.
Live chat couldn't help me, they did a support ticket which is still unanswered.
I noticed this issue exactly 33 hours ago. I dont know what else to do.