Sorry for delay in replying,
its difficult for me to comment with certainty as the only deluxe I've got is v16, so v14 may not show the same problems as I see in v16, but I don't think the red item is the problem, for example the groove leading to the red object I filled in with a box (thus eliminating the groove), I then added a new groove with smoother corners and fully formed end, the red item then subtracted without any problem.
If your v14 showe the same affect as i see in the two pics above, I'd suggest filling in the offending grooves and recutting them taking care to get the bends as smooth as possible, the pic below is what I see in v16 when sliced where the red object will be subtracted, and shows the previous groove isn't fully formed and has torn a hole in the side and I think this is what is causing the problem.
#edit# obviously if you try filling and recutting the grooves, do so on a copy of the file (save-as) so you retain your original, added pic of new groove (filled in using extruded polyline and the recut the groove), shows the red object has subtracted without problem, had to also re-subtract the long hole as filing in the groove also filled in part of the hole. #end edit#