I had a look, March stance does work.
It looks like DEI team increased the movement range of navy so i decreased that. It has nothing do with army on land. Only at sea, as transport ship.
My best bet is the matter that a Campaign start from winter. An army which has deploy stance could barely leave out of ZOC during the middle of the winter. 12 Turns Per Year means ... you will get the idea. It is not compatibility problem. My mod Just make it hardcore.
The good news are moving is still possible via March! stance, couldn't initiate siege/pitched battle though. There is an exception like an army which has +movement range bonus on the matter. It will somewhat prevent too early expansion with 12 Turns Per Year. I guess your first question is not relate to march but deploy stance.