Many thanks for the very helpful responses!
With your great input I’m realizing it was a combination of two mistakes giving me problems—cutting short the maintenance cycle and over the week or two of not charging, allowing fuel level to drop below minimum for running maint cycle at all...
Owned my ‘15 abt 9 mos. Rex maintenance cycle has run periodically in that time as needed & once charge level dropped below 75%. Recently though the maintenance cycle started to run but bc I was only running short errand trips, I wasn’t allowing the cycle to complete before shutting off power...