+1, I didn't notice the pattern - that first pinned tab becomes unpinned - but that's the case.

(I tried to reproduce this with both options for startup, but I cannot make the duplications either way.)

I read the other threads about this on the weekend so I can live with it now.

Vladyslav, I cannot reproduce it now.

It was chromium, but I experienced this on chrome too.

The setting is Open new tab for startup, I changed this for every chrome/chromium/canary instance after the upgrade last week.

Sorry, this is a bug I think, but I cannot move it from Ideas now.