Spoiler -- Yurgir Fight/Displacer beast bug?

[Captain Weegee]

After getting crushed the first time I tried to persuade the big guy to not fight. After that I walk over to the displacer beast and also successed in a persuade check and told him that he actually got charmed by Yugir, so he want to kill him and you, everyone.

I failed the 20er roll to get him on my side, then a fight begins, but he is only attacking me, ignoring Yugir and his Merregons completely. Why are they still fighting together??

Is this a bug or what? Why do he tells me that he sees everyone as enemy but in real he is still just MY enemy when the fight begins.
(For some reason I have the feeling that it's impossible that enemies fight each other in this game, am I right?)

[Ichthyic]

where did you start the fight? it likely attacks whatever character is closest.

[Captain Weegee]

Well yes I was the first target, because I stand next to him when the fight starts, but even when I gain distance with my whole party the displacer beast and the Merregons are just ignoring eachother and following me.
They do not even trigger a reaction attack when they pass each other.

EDIT:
I was hiding with my party while my Tav got eaten alive, after his death they just stop fighting and walk back together like pals ._.