When multiple cells are introduced one by one as mentioned in page 29 figure 3 in the datasheet, during insertion of the first cell, the micro-controller IC boots as voltage is induced across the pin and current flows.
Some times the second cell or multi cell insertion could cause bad booting and there might be some high currents drawn. This can be oversome by introducing the balancing resistance of around 100 ohms across each cell and making Cellx pin open.
The packcfg.chEN register has to be set accordingly based on the application for these kind of multi-cell configuration.