Advice: What To Do, If Anything.....
Who else is gonna fix it? It's either me or wait until the ceiling in both bathrooms falls on the floor. That's more work I know nothing about.
i feel your pain, but if it were me, i wouldnt touch it
you mentioned the problem was an over tightening of the screws on the mounting flaps of the vents?
did someone tell you this or did you deduce this yourself?
those vents need to be replaced, and whoever over tightened the screws should pay for the new vents and the installation
if they allready came out and ran a bead of silicone over it then there is your proof AND your goodwill
you allowed them to try to patch it up, now it needs to be fixed
call your insurance rep, explain the whole deal, and explain to him what we just discussed, and im sure they will go to bat for you because it is their investment