I’ve just checked on my compass collection (3 Silva, 1 Moscow) and they are bubble-free.
I’m surprised as the Silvas are 10, 35 and 45ish years old, dating back to my ML, my first cub hike and my Dad’s ML respectively. They all work absolutely fine. Just a little corrosion on the 35yo Silva Starter needle South.
The Moscow is a thumb compass and a thing of beauty, especially as it also a SI dibber. (No bubbles there neither).