It's reading items that are already placed as still needing to be placed.
Like the whole area is finished placing brick and it's still saying it needs like 100 bricks.

1) Did it refresh? Place another ghost and see if it updates.
2) Are there other ghosts requesting bricks in the network?

So I deleted the one that required 100 bricks earlier, as needed the space. However I have 3 other networks along parts of my defense all requiring different amounts of brick. All of which have been as such since the OP.
If I remove the Ghost Scanner and place it back down it has the same request for bricks.

I'd have to see the save file.

Here ya go
https://drive.google.com/file/d/1i7qdFlEuVP--d3gId5BwP3evZ3U5U5UF/view?usp=sharing

I guess you mean the scanners at the western "Wall Defense" train stops showing tile ghost just outside the roboport constuction area.

While I can't replicate that behavior in vanilla, slightly reducing the scan area for tiles, cliffs and item proxies fixes the issue in your save.
Next version will include a map setting so you can adjust scan area offset until it matches your modded game.
For me changing it from 0.001 to 0.004 was enough to no longer detect bordering tiles.