If issue reproduces after the update, let us know the exact scenario on how to reproduce the issue. Do I understand correctly that you have multiple screens and your main one is with FullHD resolution?
I included the desktop background so you can see the issue more clearly.
The application calls up a window of a certain size (dark gray area), but only uses a small portion of that window. If you resize the dark gray area the used space scales with it and never uses the whole thing. It’s as if the scaling math is wrong somewhere.
Additionally, if you grab the top control bar to move the window, as soon as the mouse moves, the application window jumps down and to the right by about the same proportion that the application window is off.
I’ve tried changing window managers (Metacity, Marco, Compiz) to further isolate the issue. The behavior is consistent with each.
eDP-1 = Dell XPS-17 - 9720
DP-2 = Dell P2723QE
DP-5 = Dell U4320Q
2&3) Display sizes
Screen 0: minimum 320 x 200, current 11520 x 2400, maximum 16384 x 16384
eDP-1 connected primary 3840x2400+0+0 (normal left inverted right x axis y axis) 366mm x 229mm diag 431.7mm
DP-2 connected 3840x2160+7680+96 (normal left inverted right x axis y axis) 941mm x 529mm - diag 685mm
DP-5 connected 3840x2160+3840+96 (normal left inverted right x axis y axis) 597mm x 336mm - diag 1079.5mm