When I type in the command /fill (x y z) (x y z) air 0 destroy, the command is executed successfully. The area is destroyed and blocks are dropped as they are supposed to be, but while the command is being executed there is very heay lag followed by the UI disppearing. Once the commmand has been completed, dropped blocks disappear as well. However, everything still works perfectly fine.
I play on a Hisense U989 Pro.