XG lost configuration while uploading firmware v18-MR5

Hello Community,

I've uploaded the Firmware v18-MR5 to several XG Firewalls (~30, mixed SG/XG 115 up to 525). Two XG125 "died" while uploading the firmware (installed Firmware is v18-MR4). It means the firewalls has lost their configuration. The boxes are not reachable with the configurated IP address nor with the default IP (172.16.16.16). These firewalls are located in far away offices so I can’t investigate to issue.
We restored the Firmware v18-MR4 with an USB-Sick and applied the configuration backup. After the boxes are back I was able the Upload the Firmware to this firewalls.

Thanks,

Ben