when the game first starts this problem is not there. it seems to be tied to having a lot of armies on the map and the game's inability to compute the visual army travel path

the BUG - you select army movement and then the army takes off in the wrong direction in a diagonal OR the MP counter goes to zero but the unit does not leave its origin hex

the workaround is to save and load the game at which the unit will be at its destination tile, but this makes playing the game VERY SLOW with saving and loading for almost every army move

this is my latest save file from turn 75 just entering the early modern era 

075.ctr

if you move all my armies one army at a time surely this error will occur for you as well

I do have quite a few mods loaded, but afaik no HK mod has the ability to change graphic assets or unit movement display

UPDATE - for some reason the bug is less likely to occur is the army movement is on the cloth world map instead of the full detail world map. this reinforces the evidence that this is an issue of the game running out of memory storage, likely due to an accumulated memory leak