Close Under Mouse not Working with iTunes

Describe the bug
A clear and concise description of what the bug is.

I'm having an issue where the "Close Window Under Mouse" option does not work with iTunes. It does not happen every time I try to use the button, but seems to happen the first time I open/activate iTunes after any kind of break using my computer (sleep, shutdown, etc.). It also will sometimes randomly happen at other points. This has been an issue for as long as I can remember using BTT.

Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):
Touch Bar

If applicable, add screenshots to help explain your problem. (You can just paste or drag them here)

Device information:

  • Type of Mac: MacBook Pro 15" 2017
  • macOS version: 10.13.3
  • BetterTouchTool version: 2.518

Additional information (e.g. StackTraces, related issues, screenshots, workarounds, etc.):
Usually, if I close the window once normally, it will work after that.

Note: Before bug reporting, please make sure you have the latest version of BetterTouchTool and that you have already tried to restart your system :-). If you encounter a crash, please attach a crash log from the macOS from the "User Diagnostic Reports" section.