Safari playing audio through AirPods makes fluttering sound

When I play audio from my MacBook and Safari to my AirPods, I get this occasional, short "fluttering" sound every once in a while. Not very loud, but disturbing.

I'm using MacBook Pro M4. The problem has been occurring on both MacOS 15 and 26. It is affecting three different sets of AirPods (Pro 2, Pro 3, some older ones).

This is only occurring with Safari. No problems with Microsoft Edge or Spotify. I haven't noticed the problem with other Bluetooth headphones (Bose QC 35-II).