Yup when your car was deemed totaled by your insurance company I.E. it was cheaper to just pay you off than repair it. A car that an insurance company 'decides' not to fix is NOT labeled salvage.
Then the totaled car is sold right to auction with a clean title. Then dealers go to the auction and buy the cars as-is. Fix them or not and then put them on their lot to sell. None of which are mandated to report to carfax.
IMHO carfax is a joke. The consumer is led to 'believe' that EVERYTHING is reported to carfax and it simply is not.
Only those that 'choose' to report to carfax. Some emissions stations are required to but then again not all of them in all the states.