This is one reason I'll very rarely make large plays on claiming races. They are nothing but maneuvering and business deals going on as horses move up and down through the claiming ranks. (Trainers holding horses back so they don't get claimed next time they run in lower class, Jockeys doing favors for each other and trading wins, etc..). That shit goes on all the time in claiming races.
Maiden Special Weights, Allowance and Stakes races are about as close to a true effort you'll get from the horses.