I'm not sure if this is a bug in BTT, since I don't think I've seen the issue outside of Remote Desktop (connecting to a Windows 10 machine), but I find that any three finger taps (mapped to mouse middle-click) cause two instantaneous clicks on the Windows application. This is most obvious in tabbed applications, like Chrome, which will either open or close two tabs at a time from middle-clicking.
This happens with about 90% reliability. With difficulty, I can lift my fingers very quickly and have only one click fire, but I generally fail to manage this. I have tried with different remote computers (same problem), both the built-in MBP trackpad and a BT Magic Trackpad 2 (same problem), and I have used a conventional mouse (no unwanted second click from middle button).
In BTT settings, I have enabled 'Lift fingers before triggering the second 3 finger click', and I do have a fairly low req'd pressure for 3 & 4 finger taps (0.061), since I had a little difficulty triggering them in MacOS otherwise. I don't have any gestures for double three finger tapping - in fact the three finger tap is my only trackpad trigger, and it's used across all apps.
Any advice is appreciated!