They "sag" along with the rest of the exhaust.
1) To resolve this - replace the rubber hanger near it (wears like the others quickly)
2) Loosen entire exhaust system
3) Support cat with a trolly jack, lift up to desired level (ie, parallel to car)
4) Re-tighten all exhaust clamps and it should sit fairly high
5) Lower jack and itl come down a bit but not much.
Never had any issue with mine after that. The lowest part now is the exhaust clamp!