Same here on version 44, amd64 Ubuntu. I have 2 Ubuntu installations on different computers. One is good. Comparing Preferences file with the good and bad one, in "browser tag" the following settings are missing:

"window_placement":{"height":1028,"left":65,"maximized":false,"top":52,"width":1169},"window_placement_video_popout":{"height":200,"left":810,"maximized":false,"top":440,"width":355}},

Values are for non-maximized left-top-bottom aligned window.