Question about my airlock activity....

So the past three brews I have done had zero airlock activity. The first a centennial blonde used wyeast American ale ll, the second another cent blonde I used us-05, then the third a belgian wit I pitched wyeast 3944. Now all three reached terminal gravity pretty quickly and for the ones with liquid yeast I pitched I made 1L starters. I have an all grain set up but previous brews have always fermented pretty vigorously. Now of course I know that airlock activity does not mean fermentation activity. I just find it strange that these three beers all with close to the same gravity and different yeast strains would ferment without a bubble. Looking for any advice or thoughts on the matter.

Nothing to worry about. I have 2 buckets, one bubbles the other doesn't. It just means the CO2 is getting out some other way.

+1, via the path of least resistance. Only way to truly check fermentation is by taking gravity readings. Thief a sample to check in.

Another vote here for a leaky seal.

I have a couple bucket lids that don't seal well. No bubbling. The only thing that worries me is oxidation, but I've never had any off flavors.

Yea the buckets was kinda what I was thinking to. I trust my hydrometer more than anything.