I have a 2 month old 31SQB that we noticed the top flip-up bunk was sagging. The stickers on the walls say 300# limit. My son's are 120# and 220#. On our last trip my oldest used this top bunk.
Unless my math is wrong, he should have been under the weight limit.
Here's a pic of the middle hinge of 3. I attempted to tighten these today and they are stripped inside the wall and will not tighten. The screws on the other 2 hinges are tight, however, and appear to only be attached to the paneling. I can pull the whole bunk out from the rear wall and watch the paneling move.
I have instructed everyone to not use this bunk for anything but holding clothes while changing.
Please check your bunk attachment points.