It wouldn't be so bad if other minions could attack and kill them. But since they are ignored by everyone, it could be pretty dangerous.

There is a save file where it can be reproduced:

through the back door_20170204163221

through the back door_20170204163221.meta

You will need this map to load it.

How to reproduce:

There is an unidentified artifact nearby the research shrine. Workers ignore it from the beginning. Also there are 3 artifacts in the archive, one of them is unidentified. Archive has 3 shelves too, so there is not place for the fourth artifact.

So, if you use an identified artifact from the archives, it will free one shelf, the worker will grab the fourth artifact from the research shrine and put it into archives, ie everything works as intended.

But if you wait until arcanists identify the last artifact from archives (it's an artifact of sin) and use it, a worker will grab the fourth artifact from the research shrine and will attempt to put it into the research shrine instead of archives.

No idea why it happens, but it happens every time I load the save and use the sin artifact after it has been identified.

I see, thanks for the explanation :)

Indeed, once I built much bigger vault, I got all "missing" heroes, including Warden.

I thought I had the same issue when I played the map for the first time recently. Turns out you have to put rally flag before the vault door, not directly on it.

dlc1_campaign_level2_name_20160718183054

dlc1_campaign_level2_name_20160718183054.meta

So far new saves work, but I saved many times on the corrupted one after creating it.

And the save is corrupted. Nothing we can do, I suppose.

Oh. I wasn't aware that unfinished constructs can be targeted by enemies at all.

You right, in this case it cannot be replicated so easily, my bad. It happened while playing on save file made in 2016 from this tread http://brightrockgames.userecho.com/topics/1804-cannot-load-a-save/

so it might be the problem.

Well, not sure there is a way for me to find out the version, there is nothing like that in the loading menu, and of course I don't remember which version the game had back then.

I made original save file 7.18.2016. Yesterday I loaded it and at some point saved the game in a new slot - that's where the uploaded corrupted save came from. I still can load that old save from 2016, but not this new one.

This save survived at least two patches, so it may be corrupted due to changes in the game code.

Even so, ctd is a bad thing :)

Just now I replicated it again without loading a save:

- started a new game on the Summoning Stone map (second map in the dlc)

- destroyed the closest artifact shrine with stone knights to get access to the route where spawned heroes pass by all the time

- constructed an outpost on neutral ground close enough to the heroes path, but grabbed all workers before they managed to finish it completely - I usually wait until it's half finished.

Done. Once heroes are close enough, they notice it and start attacking.

I also tested it in Cassita home realm, I half-built an outpost with ~50% readiness right before the gates on neutral ground and then summoned a wave of heroes. It's less effective there, since only sappers attacked the blueprint. All other heroes ignore it. So I suppose sappers in Cassita home realm and all heroes on the second dlc map can see unfinished constructs...