Symptoms: Audio (system-wide, not software specific) is occasionally interrupted (and when silent, a popping sound can be heard) every 10-20 seconds.
When observed through pavucontrol or similar tools, it can be seen that the port switches from Line Out to Headphone for a few milliseconds.
Troubleshooting: Unsure, past research (a year ago, links lost) lead to some very old kernel bug, but really I can't remember much. For me, it occurs on all distributions I tested (Mint, Kubuntu and now Manjaro), but not Windows.
Seems like the Headphone port is shortly recognized, pulseaudio (or alsa, not really sure) decides to switch to headphone, only for it to revert back immediately after the glitch reverts.
Workaround: Worked for the past year without a problem - it's probably not fixing the source problem. Will post it as a self-answer for now.
Any input as to how the source problem could be fixed are appreciated.