usualy most "smart" chargers today have a limit of capacity
see if it is set up for 100% or 90% at the NIMH AUTO charge mode
this is maybe why it wont go "fully charge"
or
creat your own charge cycle by setting up the correct parameters:

1100mAh
7.2V
6cell
1.2-1.4 per cell

start with a charge rate of 300-400mAH
and no more than 600mAh

see if it works