I should mention that I'm still on 3.5.5, but recently got a new laptop (with Windows 11), and the issue seems to have disappeared.

Default Chrome tab ("new tab"). I appreciate the quick responses!

Just tested and it looks like only when it's a new window... Current window seems to be fine.

I have a bunch of collections (at least 15), each with 2 tabs. I also have a few collections that have 6+ tabs. For all of them, the first tab doesn't open when I try to launch the collection the first few times. Takes about 3 or 4 launches before the first tab actually opens properly. When I say "3 or 4 launches", I mean closing the group of tabs and re-launching the collection 3 or 4 times before all of my tabs open properly.