UnitAI synergies?

[Tholish]

I made a unit for my future mod that was a combat unit with worker capabilities. To keep things fair I gave it the Worker UnitAI. Everything was fine for a long time but recently my game had an infinite "Waiting for other Civilizations" freeze up(is there a name for that?) and I used World Builder to isolate exactly what caused it. I found that if I changed the unit ai of one of these hybrid units in one particular city from Worker to anything else, during the turn right before the freeze up, the freeze up didnt occur. (the city and unit belonged to an enemy and was adjacent to a unit belong to one of my vassals)

So, does anyone know of some rules of thumb for combining Unit AIs? I'm thinking maybe you shouldn't mix Worker with Attack.

 

[musicfreak]

My guess is it had something to do with the "run away when enemies are around" trigger for workers conflicting with the fact that you made him a military unit. But someone else could probably give a better answer than me.