Teq's Minor Assembly Shenanigans

I’ve been having some trouble with using convoy partitions alongside the modular save with 200 items.
Here’s my setup:

The first and third partitions work, but for the other three, if I withdraw from the supply, the game will softlock with the withdrawing unit running in place and not ending its turn. If I try this same setup in a new ROM that only had modular save installed, I get the same results, except the game crashes instead of softlocking. I’ve also had some odd results while experimenting with minor changes to the setup. Like if I make the first two convoys 80 items instead of 90, they both work, but the third won’t work if I make it the last 40 items. But if I leave the third as the last 20 items, all three work (with items 160-179 not used outside of the combined convoys). Anyway, I’d appreciate anything you might be able to offer as far as why this isn’t working. Thanks in advance.