So starting today Bitdefender (Free Edition) decided that LolPatcher.exe, LolPatcherUX.exe and LolLauncher.exe (all part of League of Legends) exhibited 'suspicious activity' and should be closed. A subsequent virusscan of the files showed nothing. Excluding the files solved the problem, but this sure seems like a false positive affecting one of the most popular games in world.
I have attached the logs.
I'm on Windows 10 64bit, using Bitdefender Antivirus Free Edition 1.0.21.1099
EDIT: A fresh scan on virustotal marks the files as clean as well.
/applications/core/interface/file/attachment.php?id=13863" data-fileid="13863" rel="">log1.txt
/applications/core/interface/file/attachment.php?id=13864" data-fileid="13864" rel="">log2.txt
/applications/core/interface/file/attachment.php?id=13865" data-fileid="13865" rel="">scanlog.txt