Yes, I experienced the exact same thing.
Once loosened with a spanner one side unscrewed using my fingers, the other side needed spannering all the way out.
The threads were damaged, perhaps been like that since inserted in the factory or maybe they're under a lot of force/ movement when suspension is working. Maybe it happened when I was unscrewing with a spanner.
I used a tap and dye to clean up the threads, they actually didn't need much work, I also made double sure everything was in line by using a G cramp to move the suspension until the bolt could be inserted and turned fully home by hand before tightening.
