Aha! I think I've discovered why this is happening for me at least. Oscar, you didn't mention using two screens but I suspect you are (?). If not, mine may be a separate issue.
When I have a chrome window on my external monitor that is taller than my primary screen and I open a new window, it's full screen on my primary screen. If I adjust the height making it short enough to fit on my primary screen, it opens as expected.
I suspect any application that creates new windows of a particular size would exhibit the same behavior, I don't know anything else on my computer that does that though. Maybe Alberto can experiment with this.