CME Gaps occur when the Chicago Merchantile Exchange closes but the BTC price continues to move (Crypto Never Sleeps). These gaps which you can see on the ticker BTC1! have a well over 90% Fill rate.
The past 2 Weekend gaps were filled on that Monday after each weekend. It also coincides with the bottom of the current range... Invalidation of this would be above 30.6k while BTC still needs to regain the 31.7k level