I can confirm. I actually got some video of the bug in action:
http://www.upload.ee/files/5494712/error.mp4.html
Riot Support is giving me the classic runaround of asking whether I've allowed admin privileges, updated directx, etc. ofc, I have (I wouldn't be contacting them if the solution were that simple).
The only solution I haven't tried yet is reinstalling League. Usually when a file becomes corrupt (which is the primary reason reinstalling works), the program will crash, rather than continuing to function properly. I don't imagine reinstalling will help, but I'll do it when I have a couple spare hours.
EDIT: fixed by repairing game files. At the launcher screen, click the '?' near the top right. Then choose repair.