How many days were the boots skied in? I could see if it's during the first 10 days when the boot is still busy conforming to your foot, but as the heel pocket opens up and you get the heel further back, this should go away. If anything, removing the spoiler to accommodate a larger calf should allow the heel to get back in the pocket MORE, at least for any boots I've taken spoilers out of.
Try to lean forward and scoot that heel back BEFORE you buckle, to keep the toe away from the front of the boot. IF NECESSARY, wack the heel on the floor a few times with your foot in the boot until you are sure the heel is as deeply seated as it will go. ONLY THEN should you start tightening the boot.