For a long time now, I've had audio drops and sometimes even keyboard input drops through my KVM switches.
When a drop occurs, all audio across all applications drop at once. If there's a video playing then it'll pause briefly. In a game, I just miss a second of audio with no video stuttering.
When I connect my USB speakers directly to my motherboard then the issue does not occur; only through the KVM switch. I was using this decent switch I got off Amazon but just replaced it with one from Level 1 Techs and the issue remained. I've tried different ports on the switches and my board as well.
The issue also only occurs on my Linux computer. When I switch over to my work laptop running Windows I don't have the issue.
I'm not seeing anything in journalctl that seems related after swapping KVM switches. With the old switch I was seeing logs like below but no longer see that with the new switch.
Are either KVM powered by an AC adapter or are they riding off the 5v rail of your PC?
I had a very similar problem and found that the 5v on my PSU was going bad, and as devices powered down/up the KVM would vanish for a second and reconnect.