I had this happen recently to me. Turned out, the
furling line was somehow getting tangled around the forestay mount below the
furler. I have no idea how this was happening. But it would get a
single wrap around it and then become hard to furl in because of the tension of being wrapped around the forestay mount.
I didn’t notice for awhile until it wrapped a second time around, causing it to completely bind up. Then I discovered what had been going on.
Of course by then my 10mm double braided poly line was totally chewed up. So I replaced it with a 8mm vectran furling line by Marlow. So far so good, though I need to give it more time before I call it fixed.