When using the group skirmish, the game will automatically move on to a new guardian when any guardian becomes maxed at the current rank.  WHY THEN, if you fight a single guardian skirmish will the game NOT stop when the guardian can grow no further?  

I sent one 2 star guardian (max level 20) to fight with auto replenish, and 9 hours later (overnight)  my energy refill surplus had gone from 112

to 13.  NOTHING TO SHOW FOR IT>  2 Months worth of saving energy balls and totally wasted.   

WHY IS THE AUTO RULES DIFFERENT FOR single and group????????  WTF !!!!!!!    WHY would we have to MONITOR a single guardian skirmish to stop it when the guardian reaches max level????  THIS KIND of DEFEATS the idea of AUTOMATICALLY doing the fighting for us with the skirmish feature.

So, i suggest ONLY USE THE GROUP FEATURE even IF you only trying to advance one guardian.