False 'name" cannibalizing my Contacts.

Across all of my Apple devices I have a recurring problem. Initially the wrong display name comes up for a contact, in a phone call or an email. For example, instead of "Alex Borgia" -- the name of the email sender, and the name I entered into Contacts, the display name "Gautam the Giant" appears instead. It then spreads to other contacts, "relabeling" them as "Gautam the Giant". Eventually nearly all of my contacts get affected. If I miss a call from "Gautam the Giant", an try to determine what number the person called from, 100 names appear under this false address book entry. Anyone else experiencing this peculiar, crippling glitch?