XTAR VC4 Plus query

I recently bought an XTAR VC4 plus to charge the batteries for my torches and I bought his model as it had a grading feature. I just wondered if anyone else has had issues with this model using this mode?! The digit on the left is supposed to flash as the battery charges and then say ‘done when the battery is full. I’ve had it happen few times where the digit has stopped flashing, the charge doesn’t increase (no matter how long I leave it) and it never says done or turns green. Had this happen with li-ion and ni-mh.

by g-bear8