TS Version: 2.8.6
I use four-finger swipe for changing spaces constantly. I noticed that sometimes I stopped being able to swipe vertically, Eventually, I realized that horizontal swiping was also using the default space UI. After some more time, I realized this seems to happen any time I disconnect/reconnect my external trackpad. The only fix I know is to quit TotalSpaces and restart, after which it always seems to work.