This is an FYI for anyone who needs it rather than a request for help. Any comments or insight are gladly appreciated.
I have been tasked with taking inventory of several dozen iPad a16. These things have been sitting unopened for years. As I'm popping them in the charger, adding tracking tags, setting them up, doing updates, I have noticed that the tablets put into Magic Folio cases get stuck at 1%. I had one charging for a whole day.
It wasn't until I removed the cases and powered off the tablets that they started charging. It was quite a repeatable process.
For one, since they battery is at such a low state, the device seems to need every bit of power to get past 1%.
Secondly, the folio draws power from the iPad, and apparently needs enough that the tablet can't charge.
Third, the back of the folio is connected by magnet to the back of the device. I discounted it several times, but there were a few tablets that wouldn't charge up beyond 1%. My thought is that there is current running through the induction coil continuously and the folio's magnetic attachment creates resistance here, increasing the current somehow.
Anyway, those are my observations. Hopefully they help someone in the future. None of my searches indicated that the case could be the issue.