I defended the 1k gems in the arena and claimed all 1k. After that I started to upgrade my stars, failed a few times, looked up to check my star balance and I only had 100 out of 1213 that I had. According tot he arena log it looks like it backed up 2 hours. Losing the 1k gems hurts but not as much as losing the 200 that I spent of my own gems because of this problem.