Board Game Arena

In my last solo game against 2 automas, this happened:

https://boardgamearena.com/7/barrage?table=399104188

Turn 179.

I have WInd Farm built. I have exactly 2 engineers and 2 credits left.

But the game does not allow me to use the Wind Farm - place the last 2 engineers and pay the 2 credits to gain 5 energy - the spaces are not green.

Yet, it shows that the Workshop action 1st line right (place 2 - rotate 1) available, as well as the Machinery Shop line 1 left action "Place 1 - Buy 1 Excavator for 2 credits). Both are green.

So the game knows I have 2 engineers as well as 2 credits.

There is another Wind Farm built, but the first line (free to place) is still free. So it should not be an issue of having to pay more.

Any idea why? Is this a bug or am I overlooking something here?

When the Automa is placed on a Private Building, the human player can no longer use the first slot for that building.