For the love of god, this simple numbers bug isnt a break. IT DOES NOT CAUSE A CRASH TO DESKTOP. IT DOES NOT MAKE COMBAT DO NOTHING. It is very easily worked with and even used to your own advantage if you are smarter than a brick.
^This. Broken? Are you kidding me? That word has become meaningless.
Here's your solution: Don't engage in the darn mountains! When I get in that situation I accept the loss and pull out to fight another day in better conditions. You should not be rewarded for dumping thousands of troops in horrible terrain, throwing all strategy out the window. The OP is complaining about something that is perfectly WAD.