in the way back when.
I was writing a review of a Hunter for CW. The boat had the Bergstrom/Ridder rig with all the diagonal stays and whatnot but an in-mast furling mainsail. The B&R was designed, as far as I can tell, to put curvature in a mast that does not have a backstay. An in-mast furling mainsail does not tolerate curvature in the mast -- as you discovered the hard way. The mandrel is fixed top and bottom and is straight. As you bend the mast, the straight line moves toward the aft side of the mast cavity and, if you bend it far enough, outside the mast cavity -- which is what your halyard was showing you. And the furling manufacturers state in their manuals that the mast should not be bent.
I asked Hunter why they even put that rig on the boat when 90% of their boats were sold with in-mast furling. CW assigned someone else to write the review.