Hi,
Cubase 11 Pro here. If I select a lot of MIDI containers, hit play, and there is a tempo ramp that occurs during the passage, there are some creaks. I assume that in that case, the CPU is more loaded. If the MIDI events are not selected, it is fine.
It does the same if the key editor is open or closed.
In a passage where the tempo is not in a ramp, it works fine.