Hi Alina,
FYI, another user who was dealing with Arduino errors found that connecting her Arduino’s via a powered USB hub solved the issue. Before switching to a hub, the boards were connected directly to the Mac. I would have guessed that a direct connection would provide adequate power, but apparently it didn’t in this case.
This makes me wonder if your Arduino issues are also related to power and not USB bandwidth. If you still sometimes see these errors, maybe try connecting your boards via a powered hub?
Cheers,
Chris