Shortly after the iPad Pro launched in November, Apple acknowledged an issue facing some numbers of users (luckily not myself) where the tablet would become unresponsive after a period of charging. At the time, Apple said it was aware of the issue and was investigating.
Three weeks later, Apple has updated its support document that details the issue with some good news. While the fix was previously to hold both the sleep/wake button and the Home button for several seconds until it restarts, Apple now says to update the software to hopefully totally fix the issue.
Following yesterday’s release of iOS 9.2, Apple has updated the support document to add that the latest software update “might prevent this issue from occurring in the future.”
Come to think of it, I’d personally been running the beta version of iOS 9.2 on my own iPad Pro and hadn’t experienced the issue. The last beta version of iOS 9.2 and the shipping version yesterday featured the same build number, so hopefully iOS 9.2 is the fix for new iPad Pro owners.