Both located in the garage & both lose a couple minutes a week. Been this way since buying the house in 2012. What would cause this? Would opening/closing the garage door cause temporary power loss? Wife playing a very long game prank with no payoff?

Garage door controller was upgraded a couple years ago & it loses time same as the old one.

It's almost definitely not the answer, but it almost sounds like the frequency of the incoming power is low. This does happen periodically and it does affect some clocks, but it is almost always evened out with high frequency. This is a grid-wide constant and not unique to your house. Some clocks use this utility frequency for counting time instead of a quartz crystal.

Do these clocks have a battery? Are the terminals clean and batteries new? Maybe a little more info on the model numbers would help.