iterm2 first tab transparency differs from default

I set up iTerm2 colours/backgrounds, however the first tab is always "lighter" (i.e. more transparent) than all the other tabs. When I set transparency in the profiles, I can see every tab except the first one adjusting. Is it some bug or some setting I'm missing?

In my case this was due to HotKey windows was created after pressing hotkey, but after CMD+T new tab was created with Default profile. So you can either set HotKey as default or rework your shortcuts. You can experience with this by clicking right mouse button -> New Window/New Tab and then Default /HotKey Window profile. After you will define what you would expect here it should be easier to configure

Just sorted this myself. The trick is in "Preferences > Profiles > Hotkey Window * > Window", uncheck the box for "Open in a new window, never in a tab"

* ^{Note that "Hotkey Window" is just how profile is called for me (using a dropdown terminal), if might be "default" or something else. Try each profile until the one you want is affected.}