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Before doing anything else, make sure the mast and mast base spin freely. Do this by leaving the sail furled and contained, without the sheet attached to it. Just set it in the mast base receptacle, lock it in, and spin it. Does it seem to be dragging or scraping on anything? If so, you may have found the culprit, and most likely it would be the furling drum bottom dragging on the mast receptacle top plate. There may be a fix for that but I'll wait until you've either pinpointed or eliminated that potential problem.
Could very well be this. If so, adjusting the turnbuckles inside the hull is what you need to do. Twist them to shrink length to have the furling drum sit higher, or make them longer to have the drum sit lower. You should only need to make minor adjustments.
As Matt said, friction is the likely cause. There's quite a few points on the TI sheeting where friction could come into play. Just make sure everything is routed properly and there are no obstructions