This pic concerns me. The bracket should bolt to the transom, and go right tight against it. bracket uses the transom for leverage and is sealed all around.
It looks like its not tight from that pic??
There is going to be a ton of weight on them bolts if the bracket is just hanging there. also there is some holes on that transom that should be fixed and I think I would have done that before mounting the bracket.
If was me i would remove the bracket and make sure transom is solid, fill all holes and what else might be needed, then remount the bracket with what ever you may need for shims and stuff.