I assume you are referring to the electric powered sliding door, not a lock/unlock problem. If so, check out this post in the Sprinter Source forum, which states that there is a software update that might be a permanent fix.
https://sprinter-source.com/forums/i...threads/94889/
I have an ARV on the 2019 chassis with the power slider and have experienced the problem too — turning on the ignition then opening and closing the driver’s door is a reliable temporary fix. But we recently completed a 6,000 mile trip and never had it happen. I don’t know why, but my guess is that it is somehow linked to the chassis battery voltage. If you haven’t already, I suggest you talk to Frank K. at ARV about it. Maybe he can confirm that there is a software fix.