Yes, when i was trying 2.1.2 version, it was exactly same.
Your second screenshot is more wider than my B, so i downgrade back to 2.0.5 and by the way i was trying version 2.1.1 and 2.1.0 and it same as 2.1.2.
I dont know how can you help screenshot, but here is (version 2.0.5):
A - Window width was set by mouse drag and drop.
B - Window width after restart.
Window has always same width (B) after restart, whenever i set any width lower than is on B.
I have same problem.
I setup VLC to start in minimal view mode and if i set width of main window to 200px (for example), after restart program width is approximately 450px in 2.0.5 version and in 2.1.0 and newer it is much more.
Is configurable minimal window width in minimal view mode or it is bug?