when I encircle the AI, sometimes they take no attrition even though they dont have cities in the encirclement. In north africa I had 24 20 width divisions with 3 different logistic companies, and even with max naval bases, and near max infrastructure, I was still taking attrition, while the AI had 40 divisions on my border with 3-4 infrastructure on each tile, and they were still fully supplied. this was before the war so I was not getting convoy raided.
^^ help its really annoying when my encirclements mean nothing, or bombing infrastructure/raiding convoys does nothing