Bugs about the Building Blocks mission have been submitted before, but the way the problem started for me may be slightly different.
I started playing after the original base building mission “Good News” had already been replaced by Building Blocks.
If I recall correctly, I came upon the base before unlocking the Building Blocks mission. I destroyed the base and claimed the control point.
Once the Building Blocks mission became available, I started it, proceeded to the Sjoglimten Control Point where I found my control point truck with 2 shield generators. Destroyed the shield generators but I’m now instructed to “Destroy the Command Centre”. Unfortunately, since I’d already destroyed the base this command centre no longer exists, only the resistance truck which replaced it.
I’ve tried levelling up the Farmlands region to threat 25 in the hopes that another FNIX base would spawn, but no luck - it seems completion of Building Blocks is required for any base assault/defence missions to begin.
This is very frustrating since running around killing Tanks has become a little dull - I’d really like to try the base assault and defence missions. I’ve attached a couple of screenshots showing the current situation. Hopefully this bug will be resolved soon otherwise my interest in the game will likely wane.