Hi,
Sorry delayed on adding more findings after my initial set, @nccwarp9 you might find this helpful...
The issue happened again to me after my last post, however I had inspected the gcode file on the SD Card after saving and it appeared to be correct (included the footer padding which was absent on the bad files). However the print failed at the end in the random way, when I put the SD card back into the PC the gcode was again corrupted at the end of the file.
I tried a few more slice, export and view cycles and every time it appeared OK, however when I removed the SD card and re-inserted it the file would always come out corrupted (Even when I used the "Eject" option!)
However, when I saved the gcode to local disk and then copied over using Windows explorer (remove, re-insert SD card) I did not see the issue (I only tried this once though, so hardly scientific!).
I've since moved to a different SD Card and not had the problem (although very limited printing since then).
Hence I'm more convinced it's a strange SD failure, and/or something weird in Cura's file writing that's triggering the issue. Although how it picks up strange gcode is still puzzling, but given my SD cards tend to be used only for gcode files then it's possible it's picking up data from an old file. I'm guessing theirs some kind of cache on the SD card that gets cleared when power cycled which is why the file appears to be ok initially but then bad once power cycled.
@nccwarp9 - my suggestion would be one or more of the following (a) change SD cards, (b) save to SD card, remove, re-insert, use a text editor to load the gcode and check for the big comment in the footer (assuming your cure/UM firmware does the same as mine) - or load into a gcode viewer and check the "last" layer, (c) (may not help) save to local disk, then use a file copy utility (i.e. Windows Explorer) to copy the file to SD (and then remove-reinsert and check the file). - Obviously none of these are ideal, but my money's on an issue with the SD card.
Cheers,
Steve.