Had this same situation. There is an invisible footprint that extends to the end of the footprint of the trip dropped for vacation. If you get awarded a trip that touches that footprint it will drop for carry in conflict. The invisible footprint is down to the minute. What I can not remember if there is a buffer (min 12 hours) on the end of the invisible footprint. If I remember correctly there is not. I went through a lot of "knowledgeable" people including union reps, ACPs, etc. and finally got an answer I was prepared to accept from a futures scheduler. The first futures scheduler I talked to gave me bad info, but wasn't confident and put me in touch with a more experience one. Bid accordingly and I hope the info helps.