Left click not always registering with external mice when clicking different app window

I noticed this since release 2.467 but not sure 100% when it started.
If I disable BTT or use an older version (currently on 2.366), it does not happen.

I've tested it with external USB mice, with a powered hub or directly connected.
Yes, tried restarting, etc. Been happening for a few weeks before I realized it wasn't just mac office excel (which is really buggy)

It usually happens when I click a window behind the current window. It gets brought to the front, but then additional clicks don't do anything for several seconds.

It is intermittent, but it happens every few minutes.

I also use multiple monitors.

Does not seem to happen when using the built-in trackpad, though haven't tested as much with that.

Device information:

  • Type of Mac: MacBook Pro (Retina, 15-inch, Mid 2015)
  • macOS version: Sierra, 10.12.6
  • BetterTouchTool version: 2.467 +