For a while, even after restarting the game, the respite button would do nothing. It almost looks like it's substituting the option with unstuck. Now, it randomly works again, and I have no idea why. The crossways button always seems to work, but when respite is bugged, I gotta run all the way back (assuming I'm already in the realm).
Maybe you need to check where you placed the cairn? I do remember some issue with it being too close to a wall in version one of the game would just clip you into it or not work at all. It seems to need space all round it to finction and be placed pretty close to your actual house. I also had a buddy swapped his abeyance realm and it kept sending him back to the old one so maybe this is a related bug rebuilding a new cairn and renaming it seemed to fix it along with demolishing everything in the old abeyance realm we'd previously built.