Base building - Random red unusable squares

Östra Mark Control Point

These red squares showed up on the ground straigh from when I started building my defenses. I had not placed a piece and removed any structures. Restarting the game did not make a difference.

I had this some times after removing a structure.
Placed a wall, decided later to place there something different, removed the wall but then wasn’t able to place anything else there because of these red squares.

It’s been reported. Were all having this issue in some capacity. So far it doesn’t seem to be any one type of placement, it affects them all