Comment 3 for bug 1532974

FWIW external screen isn't a factor, same happened on my laptop with just the internal screen.

It's unity8 alone that holds information about previous window geometry, it must be that somehow it respects the resize request from (qt)mir ("placed ( 1920 , 1080 )") before applying the previous geometry ("resize old (1920,1080), new (634,498)").