I've seen a few other posts on this but no Psyonix response. We've been limited to playing only on Aquadome, Champions, or Mannfield maps recently (maybe since the latest patch?). This is even happening in Rumble. Just played about 10 games there and took note of each arena, and it was only those 3. No non-standard maps showed up at all.
Thanks for the report. We're going to look into this to make sure the correct map rotation is in place.