Troops moving by water insist on taking scenic route through desert

[SonOfAGhost]

As the title suggests, I've come across a bit of a path finding/altering issue and I'm curious if anyone has seen anything similar or has any ideas what to do about it (my army is about to die due to running out of supplies because of their little detour)

Previously, on more than one occasion, I have moved troops from England to India using the coastal/river transport option. Stopping a couple times on the way around Africa to restore cohesion/supplies.

Recently I established protectorate status in Bahrain and Dubai. Since then, when trying to move troops back and forth between India and some rebel held territory on the African mainland by Zanzibar, the game keeps forcing the troops to march across the middle of the Arabian peninsula. This is happening with troops moving in either direction.

Here's where things get really weird. It only does this while the turn is running, not when giving troops the movement order.

If I drag a unit in India to its destination in Africa, or vice versa, the path drawn looks normal. All over water, and indicates a travel time of, usually 15 or 18 days.

After running the turn, the troops are always on land, depending on direction of travel, they're either in my Arabian protectorate, or on the coast due South of there (which I neither own, nor have a passage agreement for), with the path now drawn through the (still unexplored) desert in the middle and a remaining travel time of 3-5 turns and lots of messages about taking hits due to harsh weather (they are in the desert after all)

Water movement is still selected (makes sense, because there's still a portion over water after the peninsula but a PitA having my water transport tied up for months by troops in a desert), de-selecting it cancels the move. Whether or not I de-select/re-select water movement, if I reset the destination the army again finds the natural path, all over water, along the coast. As soon as I click end turn, they've resumed their headlong rush into the uncharted wastes.

I've even tried dragging the army manually to each sea zone, hoping that it might follow a series of waypoints better than just a destination. They STILL wander off into the sand.