SUMMARY: Available Mats Inventory is not updating while the “unfulfilled” piece is still out for placement.
Let’s say I want to place a wooden chest. If I’m short on wood, the HUD count will tell me. Imagine I have the chest out for placement, it’s glowing WHITE to signify “unfulfilled mats.” If I go out and chop some trees, the box will never turn GREEN on its own, despite my having mats in inventory. I need to switch views in the building HUD or run away from the tree area before it updates and shows “buildable,” or green.
This is similar to, but different from the ad hoc craftable Bug noted by @Bodin.
I know a lot of builders will be confounded by this, and I’m hoping it will be nipped in the bud before Live.