BSOD on Surface with 1803

Of the 5 Surface 1807's (Surface Pro Advanced with LTE or something like that) we have deployed in the field, the 3 that have been upgraded to Windows 10 1803 are crashing every few days with a BSOD indicating a storage problem or that a critical process crashed. In some cases the device is idle when it crashes, in other cases the users have reported a freeze for a few seconds before the crash. No memory dump file is written (crash never progresses past 0% writing dump file). We are seeing the same thing with the previous model Surface (1796 or something like that)
 
The affected surfaces are using Samsung NVD SSD's and so are not affected by the (now patched anyway) issue that affected Toshiba and Intel SSD's.
 
There is nothing to indicate that the crash is related to WebRoot, but it is the only non-MS software we have installed on these devices that runs at a low enough level to cause this sort of crash, and definitely the only thing that inserts itself into the storage path.
 
I have just reimaged one of them back to 1709 but won't know for sure if that has fixed the problem or not for a few days.
 
Has anyone else seen anything like this?
 
Thanks
 
James