The A4 may be a ‘Class Compliant Device’, meaning no need for specific drivers, but how your particular DAW or particularly, your ‘Settings’ and Routings…not to mention how say, Ableton recognizes the A4 when there’s any form of ‘time out’ on the A4 screen, as just an example of the myriad variables.
Am still learning A4…however, with external hardware and in particular, hardware sequencers/synths with strong clocking/timing, when there’s certain disrupts, restarting your DAW and/or unplugging/plugging back in USB to get all ports to recognize and speak to each other properly…? Just an idea.
Merry Christmas…green or snowy.