Just kind of a funny story that serves as a good example at how silly the pathfinding problems can get.
This scenario starts with a full on beach assault. I send in everything I have. All the walruses go in first. Two of them have anti tank guns, and one of them is AA, and one has a repair gun. Immediately I take control of Manta 4 and have the other mantas assist me, and use them to cover the walruses from the air. All resistance on and near the beach is wiped out completely, and I send some mantas to rearm, while ordering the two anti tank walruses to head towards the next outpost, the AA being sent in soon after, and finally the repair walrus bringing up the rear. I switch focus to the mantas again, and take them towards the outpost to give cover from the air again.
This is when I notice that the only walrus that made it close to the outpost is the one with the repair gun and it is getting shot to pieces. I get there in time just to see it destroyed but not soon enough to do anything about it. Meanwhile further back I see the other 3 walruses being stuck on eachother. It appears the first one got confused which way to go on a straight road, and the other anti tank and anti air couldn't figure out how to go around it. Somehow though the repair walrus managed to get around that whole cluster and proceed to charge the outpost alone.
As I try to sort out the mess with the entangled walruses I leave control of the lead manta up to the AI for a few seconds, and almost immediately it starts to take damage. I switch back to it and it seems to have decided to engage a an enemy surrounded by heavy AA emplacements. I lose the manta before I can get it out of there, and order the rest of the mantas to return to the carrier, but they spend too much time circling a waypoint above the AA before heading towards the carrier and they all get shot down too.
With no air cover left I order the remaining walruses to return to the carrier as well to prepare another assault. One of them seems to have perticular problems following a road so I decide to pilot it back manually. As I get to open water I hear one walrus is under attack, and give the controls back to the AI and check the map. One walrus apparently decided that the best way back to the carrier was not to go straight back to the nearest beach, but through the entire island. It has waypoints set through every base on the island, off the beach on the opposite side, into the ocean there and then going around the entire island back to the carrier. I take manual control of it but it is too late, that walrus is also lost.
It was pretty infuriating trying to make any progress, but at the same time I had to laugh at how bad everything went.