Whilst playing Tank Grab on the Cielle map as the mechanized company I am unable to destroy or knock out enemy Stuart tanks. It is possible to reduce their hp to about 5% and destroy their main gun and engine but that's it. I've hit them with every type of round and also artillery but they seem unaffected for that last 5% of hp.
I am able to reproduce this bug by forcing the game to exit and retrying the mission. I haven't tested the other company commanders yet. I have no mods installed and the game is up-to-date.
My rig is as follows:
6 GB RAM
GTX 970 graphic card
Great game so far, really a massive improvement on the original COH and I've been fortunate that this is the first game-breaking bug I've come across. Also, the Stuarts are kinda cute when they're wiping your entire base whilst being bounced around by shellfire