Fading Screen DSO nano v2

Unit had been working fine in the past, then today when I pulled it out and switched it on the screen was quite faded looking. After some observation I noticed that it seems to be cycling through a range of contrast or brightness levels, but doesnt quite make it to either full white or normal look.
I tried charging the battery via PC but the problem still exists. The unit seems to work OK but the screen goes from almost unreadable to various levels of usable in a continuing cycle of a couple of seconds.
Every so often when I reset it it works properly, but only about 1 in 20 or more times.

Anyone have any ideas?.

Oh! firmware is BenF 3.62