I think I first saw something about this in the bug section, but it does not seem to be a bug. It is however, quite interesting and certainly presents a lot of opportunity to spade.
Let’s start with Gauntlet Simulation 07 on the Easy (Wilderness Survival) node.
Enemy team of:
Go in with 
on your team.
They should have a 
team-up.
Take out
to run 
They should have a
team-up.
Try
- do you now see a
for their team-up?
Come back with
- opponents should now have a
gives them 
gives them 
gives them 
The real interesting thing to me, is that I think it seems to be set per node, with all of the different combinations resulting in a different specific team-up for the opponents.
I tried this: Went to a few nodes where the enemy has 3 characters. Brought the exact characters they have from another node, and swapped.
So in the middle sub, went to nodes where they have:
, brought my own 
. That resulted in them getting a
team up.
Swapped it and brought
to the node where they have
. It results in the AI getting
So it’s either a unique combination per node, or it’s taking into account which side the characters are on. Very neat.
It does not seem to matter what version of a character you run. So any
of yours will negate their chance at a
team-up. It also does not matter what order you put them in (left to right).
I think there’s a lot of potential to figure out what combinations of characters on your team result in which specific team-ups.