Green line appeared on MD4

We have installed a brand new display in a battery powered rig this week. Its serial number starting with 2305 and production date of 230202.

It has been OK for a week but after the battery in the rig went flat, this line appeared:

Only thing I can think of was the battery was depleted and resulted in the display flashing when the battery got to a level where it was unable to power the module. It performed OK after the battery was recharged but after a few hours the line appeared. 

Anyone had this problem or similar before?