I have seen that with both Linux and Windows. And there are bugs like this https://bugzilla.mozilla.org/show_bug.cgi?id=1808039 that prevents sleep on Windows, but somehow does not exist on Chrome, or when you use Linux/Mac. I have determined that if battery is really important for a certain occasion, I just manually power the laptop off. Thankfully, these days laptops are fast enough to start make it tolerable.

Of course, I can't understand why Microsoft or Linux distribution contributors along with software vendors never manage to truly "fix" such important usability issues.