I had a similar experience with my tow vehicle a 2000 VW Beetle. The frame to which the tow brace is attached broke. Noticed it was loose when unhitching. The whole front end was loose. The safety chains would still be attached to the front end but the rest of the car would have separated had there been a total failure. Unfortunately a safety cable from the tow brace to the frame had never been installed. Not sure if the bolts loosened up and then the frame cracked due to unequal pressure on the mounts or the frame cracked first. I was able to get the frame welded and reinforced and continue. Because the car is so close to the ground and the attachment points of the brace to the frame largely inaccessible I never could check for loose bolts. Time to retire the VW and I’m getting a Wrangler with plenty of access and visibility.