Arrrg, this log when it was actually unclaimed would now help to figure how this tile broke.
I guess you won't play this map again but it would be interesting if it does reproduce.
But I think it may not, at least I remember I played this map my self a longer while ago and I didn't run into this problem.

Oh yes this makes sense. Then it means it must have been an importing issue.
So maybe Nano can take a look how it failed and we should see if other imported maps are affectecd (have missing props).

Hrm this is very strange, the tile is unclaimed but still owned by the empire.
This is something which can not happen due to normal game mechanics, so there must have been any error directly when the tile was unclaimed, so that it changed the template but not the owner (invalid state).

I have seen there was a Portcullis on this tile before while looking at the original map.
So I guess you destroyed it and unclaimed the tile by workers?
Right this moment something must have broke.
I studied your log but didn't found an related issue there.
Question:
Was the log from the same play session where the tile was unclaimed? Or did you save and load afterwards?

Ok we will have to look at the save game then.
Thanks for providing it.

Did you try to rally minions on the tile? Workers don't claim tiles with an hidden Blate Lotus.
When units walk on such tile the Blate Lotus pops out and can be destroyed.

Not a bug.
The neutral player is a valid player faction which can own tiles, rooms or what ever.
The only thing special about the neutral faction is that all units owned by this faction are instantly converted
to any other faction which comes into view range of these units.

So a claimed neutral tile is a normal thing.
When a tile has no owner it wont be claimed.
In map editor no owner is used by selecting "Terrain" as faction.
The "Neutral" faction is a normal player with some different rules attached.

Not that simple.
It makes things much simpler, because these pigs are only supposed to be eaten by their owner (or grabbed by their owner, or possesed by their owner, ....) they need to be replaced on owner change.
We could "convert" them but this is way more cumbersome.

Why do you think this is a bug?
And why should it bother anyone? It has no drawback for the player.
I suggest to decline.

It is mentioned in campaign level 4 where you need to beat underlord Marcus, but it is not required to complete the level.
I think many people just ignore such hints when they are not forced to use it.

This is not a bug, you need to place an Outpost construct there to get this artefact.
Simply use prophecy and then place the construct as long the area is revealed.
It allows to claim areas not connected to your remaining claim.

Btw. does selling and replacing a tile fix this room for you? (it should)