Keep in mind that Apple sells a massive number of AirPods. On the order of 100,000,000 units per year. The prevalence of tinnitus is estimated to be in the range of 10% of the population.
It's also possible to impact earwax against the eardrum when inserting anything into your ear, Airpods or otherwise. Earwax compacted against the ear can worsen or modulate tinnitus. That would be my most likely explanation for any sudden-onset tinnitus following earbud use.
Source: https://www.mayoclinic.org/diseases-conditions/tinnitus/symp....