Woooooosh! I saw "flimsy metal bracket" and missed "TV" altogether. Need to get some glasses, getting old..
So, on the TV release coil is the one making noise or the UPF right flipper? If the TV release coil, I'd make sure the plunger isn't upside down: https://pinside.com/pinball/forum/topic/tspp-tv-release-makes-a-buzzing-sound-when-a-ball-enters
...and if it's not that, try cleaning the coil / sleeve / and generally making sure things holding the coil are tight (so it can't vibrate around)? Mine does also make a decent "buzz" when it releases the ball, but it's only for a second... some noise from that coil is pretty normal, after all it's housed in a metal echo chamber.