Just in case a mod install had a problem some time in the past, try the following:
This will put your game files back to stock. If any files had to be updated, it will tell you, and this indicates a possible problem. Without activating any mods, try testing the problem scenario to see if cavalry still has a problem. It should only be necessary to play the scenario once without mods, just as a test....try the "verify integrity of game files" function. Right click the name in the Steam client, select "Properties". Click the "Local files" tab and click "Verify integrity of game files."
Two possibilities:
1) The cavalry still has a problem, in which case we need to keep looking. Maybe Mike's change will help. It would be best to test any fix Mike comes up with the same way, verified files, no other mods.
2) The cavalry problem goes away. In this case, activate the mods you wish to use. If the cavalry problem does not come back with the mods activated, the problem is fixed and you're done. If the cavalry problem comes back with mods activated, deactivate half the mods and test again. If this makes the problem go away, the error is in one of the mods you deactivated. If it does not, the error is in one of the mods you did not deactivate. Keep testing until you've located one mod that causes the problem.
You probably already know that you have to start a new game every time you change the mods, as mods are saved with the game's save files.
Good luck.
Hook