I noticed the shore charger was putting out a float voltage that was +0.18v above spec. At the charger it was showing the in spec voltage for AGM batteries, but at the battery and the Xantrex it was showing an extra 0.18v.
That is enough to bring the voltage up to near what a normal lead acid battery should receive, and ruin AGM batteries.
The solution was to use the custom battery option on the shore charger, and set it -0.2v less.
Heads Up, Shore Charger out of spec.
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