Vermeer 7040 blade slap

Been running a Vermeer 7040 on a KMC cart a couple years now. Has the quick clip system. Been having a problem with the inside 2 heads having chunks knocked out of the blades. It appears the blades are striking each other when the mower is started or gets bogged down to the point of the belts slipping. Anyone had this issue or know of a fix? Maybe time one head back a notch?

Vermeer 7040 blade slap