Replying to Blocked Building Construction

The planet is Myrkr for future reference, and this bug has been around since the vanilla if I remember correctly, you think they could do a better job of solve these problems before they release a game.

I think I ran across this once, too, except I don't think I tried to build anything. I figure the game thinks there's supposed to be a Space battle at the planet, but one doesn't happen, so it probably freezes that planet until the battle does occur. Or something.

My thoughts exactly. I decided to test this theory on one of the planets with this bug, I think it was Mirkr (or however the blazes you spell the force negating plant planet), and after destroying the bunch of native forces that had been left behind when I took over the surface in a Space Tactical battle, I was able to build both space and land structures just fine.

I do suspect that an actual Space Tactical battle "fixes" this, but I'll have to test that before being completely sure.

It certainly seems to.

I think I ran across this once, too, except I don't think I tried to build anything. I figure the game thinks there's supposed to be a Space battle at the planet, but one doesn't happen, so it probably freezes that planet until the battle does occur. Or something.

As it turns out, if an undetectable unit you've garrisoned on a planet's surface moves to the planet's orbit while it's occupied by an enemy fleet, a "battle" occurs, as is indicated by the crossed lightsabers icon, despite the fact that nothing really happens, and if ANY surface building is being constructed on the planet at the time, that and any future land building constructions stop at 100% progress, without ever actually finishing . I do suspect that an actual Space Tactical battle "fixes" this, but I'll have to test that before being completely sure.

I came across this while testing the Autoresolve function's ridiculosity - I'd raid planet after planet with a single Rebel SpecOps Company, leaving the fleet in orbit alone. After conquering the planet, I'd start erecting barracks, etc, obviously, and move the SpecOps to another target, which is what caused the bug.
That said, it could be limited to the SpecOps Companies, but again, I can't be certain yet.