Apocryphal
/əˈpɒk.rɪ.fəl/ adjective hardWidely circulated as if true but likely fictional or unverified.
The story of the founder inventing the recipe in his garage is probably apocryphal, but employees repeat it anyway.
Memory Trick
Apocryphal writings were ancient texts of doubtful origin left out of the accepted religious canon; today an apocryphal story is any tale that sounds official but is probably invented.