Comment 13 for bug 1770901

@ypopezios:
the idea of my proposed loop is indded to prevent the sentry from vanishing to keep it conquerable and existant. So the loop would check for existance and replace the sentry or any other of the buildings if necesary. This would only hardly noticable by the player.
The scenario is designed to let you have a real choice: if you conquer it, you get the plans for improved bread and beer production instantly, but you will suffer some bad things in the future.
I fyou gather the wares the monastery is not self destroyed, the original buildings of p3 are removed and exchanged by identical buildings of p1 (the warehouse will additionally prefilled with some benefits as well). But as the lua stopped in your game in the last line of removal it never reached the state to just set the new buildings so in this special case you don't get the reward. In your second run without the sentry being vanished this should have been the case though. Anyhow a savegame of the game would be very helpful to understand what is going on.
The "big" solution would be to have an additional AI state "dumb" to be useable in scenarios. Look at the forum discussion I linked. In this scenario we need to trick around the working AI logic to achieve the state of the Ai doing exactly nothing. This is hard to achieve though. (for example I just didn't give the Ai of p3 any wares or workers so it can't start building anything. However this can't prevent dismantling things or simply destroying them.

@kaputtnik:
the main reason for the late placement is to prevent the AI from doing weird things, like dismantling buildings. If we can fix this properly (at best by creating a new "dumb" AI state it might be possible to place them from the beginning.

My alternative solution would look like to allow the monastery AI to dismantle their sentry by just switching teams after delivery of the wares but I am not sure whether I can switch to shared economy mode in the scenario.