I also have had problems with a 1 year old e-boxer Forester with 4 incidents of a flat battery in the last year, culminating in a warramty battery replacement earlier this week. The most recent incident happened as we were on our way to have our Covid injections. Out Volkswagon van, which had not been out for 3 weeks, came to the rescue. No problem with its battery. So Subaru have a design problem either related to battery drainage as suggested, charging sequencing/prioritising or an underpowered battery.
J
