Same here.
Given these updates move incredibly rapidly, I'd imagine this is a "Proton check" of sorts. Just making sure Proton is still enabled when Steam is booted. Presumably so that if someone disabled Proton it would stop trying to use Proton to boot.
With 3.7-5 looks like it does not happen with every game.
Hello @Reiddragon, this issue is already being tracked at https://github.com/ValveSoftware/steam-for-linux/issues/5644. Closing as a duplicate.
Title says it all. Games installed trough SteamPlay receive 0 byte updates every time the Steam client is launched.
Not a big issue but annoying nonetheless.