There is also the issue of headset heat.
You wear a close fitting headset which means there will be heat trapped in the ear canal. You sweat, it can't evaporate, your ear fills up. Simple.
This may not be your problem but it is a general thing, I don't say problem, that happens to many who wear earphones, not just aircrew. One reason why they often provide cloth covers for the earphones.
PS, it can be a bonus. The heat melts the wax and you simply scoop it out.
