I'm using the current version of BetterTouchTool (with the new UI) on a late 2014 Mac Mini running Mac OS 10.14.5 with a 1st gen Magic Trackpad.
4 Finger TipTap Left is being triggered if I do a 4 Finger TipTap Right.
To be clear: I have the 4 finger TipTap Left set up to trigger Magnify. I don't have any other trackpad gestures set up to tripper Magnify, and I don't have 4 finger TipTap Right set up at all, but for some strange reason, 4 finger TipTap Right is triggering Magnify.