This has happened to me and been reported to Cakewalk. However, it doesn't happen all the time. IIRC there's some mode that makes it more likely to do this - I forget if it's dragging from the browser, or ctrl-dragging from another track, or inserting via the insert menu.
Usually if I toggle FX on and off by typing "E", the problem goes away and I can carry on. After it works, save the project...that seems to make it come back properly but I can't guarantee anything, because it's intermittent.