Unit automatically moved from neutral tile upon DOW

[Ignorant Teacher]

I was playing Stalin Immortal University and was preparing to rush Montezuma. I had the bulk of my army prepared to move to his capital and a chariot ready to destroy his copper mine. This chariot was sharing the tile with an Aztec axeman. I declared war by moving this chariot to his mine, but, instead of going there, it was sent to a forest. Is this a bug?

Right before DOW.

Spoiler :

Moment when I declared.

Spoiler :

Where my chariot ended.

Spoiler :

How to reproduce:

1- Declare war by moving the lone chariot into the mine.

 

[TheMeInTeam]

The game sees it in the order of 1. you declare, so expels units 2. move

Basically you don't get precedence over a unit in the tile of the civ you DoW. I've come into more rare but also more stupid things involving peaceful vassals, too.