I was playing the tutorial back to St Vith, then I got series of warning that supply was blocked and truck had lost. I am sure there was no enemy troops between my soldiers and supply base, and the bridge was under control. I am curious, what is the condition that supply line is cut off? I think it is stuipd that a unit start request emergency resupply only one hour after attack begins, normal and real way is that the frontline soldiers bring half or one or several days' supply before they commit an attack. And, can I choose provide or not provide supply to specific troops? I know I can change units' supply level, but still there will be supply sent to them, and I cant forecast when and where is the truck.