Yes, not a blank tab. A tab that was on a different desktop and in use. I have also noticed if I close the group and re-open a new group it grabs another tab from a different desktop.
To be clear these are all instances of the same app (chrome). Auto group is turned on. The way groups worked for me in the previous version was it would not auto group windows that were on a different desktop.
I have a feeling you already know what I'm saying but I will give an example.
Desktop 1 has these windows open and grouped (D=Desktop C= Chrome)
D1C1,D1C2,D1C3
I launch two instances of chrome on Desktop 2 (It used to just group the new instances together)
Desktop 1 now groups
D1C1,D1C2 (No D1C3)
Desktop 2 now groups
D2C1,D2C2,D1C3) (D1C3 is taken from Desktop 1)
Hope this helps, sorry if it's confusing. Thanks You
Norm