Recently, a number of games (e.g. Owlboy, Sunless Skies, Steamworld Heist, Divinity Original Sin 2, Banner Saga 1) have received updates for Windows and Linux, but nor for Mac.

This is beginning to look a bit systemic.

Linux is significantly less popular than Mac, yet Linux builds are updated almost simultaneously with Windows ones.

Does anyone know what's up?

Divinity Original Sin 2 is the same version as Windows, but apparently only with Galaxy. (It's the only game I use Galaxy for, since it's just too big to re-download the offline installer on my connection.) I thought the offline installers were automated, so that's pretty annoying.