Today I saw it again.
This situation actually happened twice with the same types.
A shy INFj walked away from the group, without saying that she was going home.
The ESTj said afterwards, that it was totally unsocial of her, and kept talking about it for a while.
It's only when duals interact with eachother that they start a likening in eachother. Otherwise it's often that they don't like eachother. I remember an SEE at my work who hated 'nerds' (that hurt me! :-)
A SLE friend of mine truly hates 'those fucking idealists' (I guess IEI's can be seen like that)
So duals always dislike eachother, except when in close interaction together.