[.285 BUG] Auto Explore

At times my soveriegn and soldiers lose Auto Explore.  It seems to happen at random times - or at least I can't find a pattern.  I click the Auto Explore button and it works for a while, then turns itself off and can't be recclicked on - nothing happens.  The game will continue, but I have to manually move all units.

Happened in about 5 different games at different times.  Twice, it turned itself back on - i.e. after several manul amoves I was able to reclick Auto Explore and it worked...the other 3 times it never came back.