@rick danger is correct on the above- it isn't your bolts coming loose, although it wouldn't be a bad idea to check those from time to time.
Rick, you also recommended some kind of mechanical backup to the JB Weld earlier. I had an idea that didn't work using a nut and lock washer because of the limited access space behind the bracket (one of mine was split, btw). Problem is a standard nut for that bolt is smaller than the opening in the bracket. I tried to slip a larger washer and lock washer in and semi succeeded, but there is no way once everything is in place to hold the nut still while tightening the bolt. Ran into other issues not worth going into.
Ideally, if there was room to pass the top hat between the bracket and the pipe and then use a spacer to replace the offset of the top hat (usually on the other side) that would work, but there isn't enough space to get the top hat in.
A spot weld is the answer. Looking for a local friend