I was having this problem blue basic hull, it was showing it teal on the hotbar and the adv. build block preview.
slot 6. Basic blue hull
slot 7. Basic teal hull
slot 8. Standard blue armor
slot 9. Standard Teal armor
It's not showing the wrong icons, and there is still a difference. However the colour of Basic Blue Hull has since changed since generating the icon for it. It looks lighter than the block does in game, this perhaps makes it a little harder to match up icon to block.
I'll change the icon to correspond with the new Basic Blue Hull colour in the coming hotfix.