No repairs. Problem has been there almost from the first few months the house was built. Plumber contractors for Lennar were called in to fix the problem but gave up [did not try too hard]. The conditions for other homes in the 265 home subdiv that have this problem are similar. I know of two other homes with this issue.
There are slight variations to the installations on duplicate model homes. The position of the tank may be moved a few feet if the AC guys put vents in the way but all in the attic, a hot space in the summer, and fairly near the roof decking penetration.
Seems to me there is a hardware problem in the original tanks or the installation is the root cause. Could be some part has failed just after installation.