I don't understand what exactly do you want to reproduce. All you need is to load a level. Until the game initializes fully, you will sit at the loading screen, but the game is already going on partially. If you had a unit pushed into lava, it will take damage, for example.

You can't disable it manually, Andrew.

Any level. Particular instances are level 4 Chunders vomiting on a Portcullis, or a Firebreather using his fire attack against the Rhaskos' Dungeon Core on the level 7.

EDIT: I just tested a Chunder against a Templar. It didn't do ANY damage with the vomit attack. So the issue is that the attacks are completely harmless.

I have since overwritten the savegame many times.

No, I tested the Sentinel and the Gnarling separately, as one doesn't have a lair, and the other does. I dropped them alone near enemy and immediately recalled them. The Sentinel after fizzling went to train, and seemed to ignore the attacking enemy Sapper, but shortly turned back and continued to fight. The same happened to the Gnarling. So in short, nobody would flee, but rather they attempted to perform some other job, but it didn't become their top priority, completely ruining the purpose of the spell.

Even if it was so, recalled unit should attempt to flee to the Dungeon Core if it has no lair.

It's tricky to reproduce. The first time I found it out was when the level glitched. Instead of a few seconds to disappear and then reappear at the Gateway, Mandalf took much more, allowing me to capture him w/o doing anything out of ordinary. So now I had to kill and imprison him as fast as possible. Here is the savegame where all conditions are met to reproduce: Savegame.7z.

• Build a Prison for two units somewhere close to the Mandalf's Archive. It should be used for the Templars there.
• Breach into the Archive.
• Use a Sentinel to occupy the enemy attention while a Worker is claiming the room.
• Sell the Archive and build a Prison here. You may need to move the Sentinel away while you are doing so, otherwise it may kill Mandalf too early.
• Kill Mandalf and imprison him quickly.
• Wait for him to disappear. Check the Prison. It should say it contains 1/1 prisoners.

What? Is this some kind of a bot with an automatic response?

It is not how it used to work before v1.4. And regardless, why then does it say it can be disabled?

I'm not going to reinstall a 6 GB game.

Savegame.7z