That is the way lipos charge. They start out at what charge rate you set then as soon as it hits 4.2V per cell (in this case 8.4V) it drops the charge rate to keep it from going over 8.4V. Eventually it will drop down to I think .2 amps on the ice and stop the charge.

Lipos charge in a CC/CV method which means in the beginning the current is at a constant amp (CC) and the when max voltage is hit it keeps the voltage constant (CV).