I had 2 Tail rotor Malfunctions in my career. Both were fixed pitch failures. One wile instructing at Hunter AAF in 1968 and one on a maint flight in nam.
Both involved worn sprockets and chains slipping to almost zero left pedal. Got both down with no damage. (Strut)
None at Bell. Their work quality was too high.
BTW,
I think I have found the source of the new Tailrotor chain. It looks like Garlick Helicopters may have been involved in them
also I think it all happened in the 90s ( about 98).
here are data from 2 sources/

Part # 1560-UH1-752-1 replaced with
GH-257-52-01 roller chain sprocket
Part# 1560-UH1-753-1
30 --
NOUN: CHAIN ROLLER NSN: 3020-01-048-3468, P/N: AV1560UH1-752-1, QUANTITY 564 EACH SOL DAAH23-98-Q-0550 DUE 061398 POC Point of Contact is Ryan B. Kivett, AMSAM-AC-AL-E, (256)955-9191; Floyd K. Carlton, Contracting Officer. 17. Noun: Chain Roller NSN: 3020-01-048-3468, P/N: AV1560UH1-752-1, Quantity 564 Each

I would not have one. Period.