I cannot remove Deco TribalBlocks. I had attempts with Multitool and Shift-right click with a block in hand, overwrite BP , spawn POI again, restarted the game and nothing works.
Until they fix this bug, you should be able to use the creative mode selection tools to delete that block. Move the selection square over that block space and "delete" it. At least, it's worked for me in the past with invisible blocks. Worth a try.
