echo in Musescore 3 and 4

in Musescore 3 an echo is heard while playing the keyboard (Yamaha psr 463, win 10 64 bit, i7 AIO (a laptop encased inside a monitor)).
Not heard when preferences window is open, alt-E-P. in Mu 4 the delay is longer,
in low pitch notes it's more difficult for me as sound longer, high pitch notes, also shorter help hear the echo, more delay in Mu4. Echo still on when preferences window is open unlike MS3.
Just tried Mu4 and takes much longer to start and to create a new score.
in Mu4 echo is gone if midi in and out options in preferences i/o are set to no device.
Mu4 is smarter than Mu3 after changes in I/O settings or the keyboard is turned on while the soft runs, does not need to close and restart.
Mu3 echo is gone if device is set to speaker midi input keyboard midi output no device, but then played score does not show notes on keyboard screen.
when Mu3 and 4 are running, the echo is the same as Mu4, and when Mu4 is closed, the more delayed echo remains until Mu3 is also closed.
Mu4, when notes are played, some remain as pressed in the keyboard screen, and disappear when the same key is pressed on the keyboard.
It's intefering with the keyboard, when keys are pressed on the keyboard the screen shows them still pressed, keep ON on the screen until pressed again.