I realize this is quite and old thread but I just wanted to add that I have now had five SD cards ruined on my Duet2 WiFi. All the cards were quality brand cards. All the cards were dead to the extent that my Windows computer knew something was placed in the SD slot but none of the cards could be read, reformatted, repaired. I even tried third party software to try to recover or restore them. All dead.

I will be replacing the Duet2 WiFi with another board to see if this resolves the issue. I am hoping it is not a short from outside of the board since that will be challenging to track down. I did not pull the SD cards or replace them while the printer was plugged in. Each time the SD card failed I also received a message about losing WiFi connection. The WiFi always returned when I replaced the SD card. All the SD cards were in the Duet2 slot, not the Paneldue slot. I have never used the PanelDue slot.