I had the POA66 codes for wet Hybrid battery. Dry it out. And I mean dry it out properly, bone dry.
LS-X trunk door hinges welds, seams, aerial area, roof rack plastic infill area.
Remove rubber bungs on metal floor behind battery. The drainage is poor. Look for ingress too around lights clusters.
Plumber's LS-X good sealing stuff.
Clear codes with TIS.
The above happened to me. Thought the battery was dead. Now fully recovered and car working like a beaut (126K miles). Had an industrial drier in the back of the car. Drier than a crisp after I'd finished.