Quite right, it seems that the "men falling" bug has been replaced by the "got vertigo, don't want to go up the towers bug".
I find the only way to get round this is to move my men away from the towers and try again (while getting shot up), and this only works some of the time.
Personally I preferred the earlier bug as it was much rarer. Men refusing to climb the towers seems much more common.
Shame on you CA.