I had a super salmon about five years ago that regurged something very similar to what you are describing. He did it two times in about two and a half months if I remember correctly. Basically a big compacted fur ball. I know it was a regurge because I watched it happen. I think I may have deleted the photos of the event because I can't find them.
When I posted this on the forum I didn't get a solution. I called a couple more experienced people and they said they did not know what it was and had not experienced the same thing. I also spoke with my reptile vet to no avail.
I fed smaller meals less frequently for a few feedings and it never happened again. I have also changed my food source since then. Other than the gurges he was in great shape.
The good news is my boa went on to sire a perfect litter of eighteen babies. In hind site I believe it was an irritation from the hair, too large of a meal, or a combination of the two. I have become MUCH more conservative in how I feed my boas over the years and I was told I was a conservative feeder back then. So I just don't know???
I wish I had more info for you.
Good luck!
Steve - sdi