Saw this problem mentioned on another board so I'm passing this on. Many Tok's seem to be afflicted with this, and it's simple to fix.
Just use a small, fine diamond hone to put a slight radius on the opposing corners of the disconnector and sear where they rub together. This allows the disconnector to drop down and do it's job (which is to push the trigger stirrup down out of engagement with the sear).
Keep the axis of the radius perpendicular to the bore, and don't remove too much.
You'll have to take the thing apart, it's not too difficult. Lower the hammer and push the big pin out to start.
Here's a photo, you can see the radius on the sear's little 'corner' to the right of center. The little plunger that goes up and down past it is the disconnector and has been radiused where it touches/rubs the sear, right in the center of the photo(in the shadow, sorry). (Disconnector 'corner' is inside lower-right of part #24 in diagram. The edge on the sear is the dark spot, lower-center of part #23 in the diagram.)
Test by lowering the hammer - keeping the trigger pulled back - then rack the slide hard with the trigger held back. The hammer should stay back - not 'follow' - when the slide goes forward.