Slitherine

I'm not 100% sure of that but I've seen this in 2 streams and I think also experienced it myself that the AI, when in Multiplayer and set on the same team with no humans in their team, don't actually team up but fight each other.
I cannot guarantee that it was not forgotten to put them as allies but due to multiple occassions of this I think it should at least be looked into.

thanks for the report, it's already been noted and atm are working through all reported bugs and issues and the developers will see the posts and add to a patch asap