I am fighting a long and bloody campaign against the Mongols, and I have designed most of my armies so they would excel at defending river crossings (archers, stakes, siege, spears, etc).
This way I succesfully manage to let the Mongol Hordes attack my positions, but once the battle actually starts, the Mongols just sit on their side of the river forever.

It doesn't matter if I have Battle Time Limit turned on, they won't attack. Some enemy units do seem to be "stuck" by having just 1 or 2 soldiers from a unit move around in circles, as if they can't get into position.
They sometimes do attack if provoked, but that means sending my units across the bridge to get shredded by their cavalry archers. I am always the defending party, they should be coming across, right?

Any suggestions or advice?

Thx a lot!
(SS6.4 with Bugfix)