Interesting.
Part of my past experience included audio engineering pertaining to hi-fidelity project design.
One day I decided to take my db meter with me in my van and measured the noise level at my left ear (I had concerns) while driving at freeway speeds.
To state that I was stunned is an understatement, but it was expected nonetheless:
The noise level exceeded 110 decibels (I can’t recall the exact number, but it would vary with vehicle type regardless).
Thankfully a later hearing test detected no noticeable hearing loss in my left ear, though before my health recovery the tinnitus which manifested every number of days-to-weeks was weighted to...my left ear.
It is now largely gone, the number of incidents being merely 1 since the start of the ‘virus crisis’. Oddly, the tinnitus I experience now seems to affect both sides equally but, again, hardly once/year (if even).
It could be stress related, but you are lucky that it comes up only every so often per year. Maybe the stress of the COVID pandemic had an effect. Mine is definitely related to stress.