You are seeing premature charge termination due to the long term storage of the cells. The active materials have reverted to an inactive state and electrolyte has migrated from the electrodes... in other words they need waking up. It might be that the storage at low potentials has lead to internal short circuits and this may mean the cells are at end of life
I suggest you charge the pack at 0.5A (500mA) for maybe ten minutes.. then stop charging and measure the cell voltages - they should all be similar and all above 1.15V. If any are lower then the cells are suspect and you should consider throwing the battery away.
Assuming the voltages are OK then charge the battery at 1A in the normal method. Dont charge at anything higher than this for the first charge. Assuming everything works our OK you can later start charging at 3300mA but never higher than this.
Neil
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