I did try a non-balance charge once that night I believe with similar results.

The charger isn't hanging at the end of the cycle, it's actually struggling to get the voltages up it seems.

For example, with the pack starting at 3.8V per cell, it took about 15 minutes just to get up to 4.0V per cell, all the while the charger is still supposedly drawing 4.6 Amps. On a normall charge cycle it would take less than 10 minutes to reach that voltage.