mission "intercepting forages"

[Krzych]

I have also little problem with this mission.
"I need to intercept small army of forager is about to leave the village of Schlochau (Człuchów in Polish game I suspect).."

When I was assigned with that mission I go and spot these foragers, but they were too strong for me at that moment, so I clicked X and cancelled engagement to increase few levels before fighting them again.
Unfortunately, now when I try to attack these foragers, I get the popup:
"Sergeant":
"Commander! These are our enemies, we can not talk to them"

... and the only option is to "Retreat"...

Is there any way to force them to fight?
In case that I messed this mission inevitably, I would lost hours of gameplay, because autosaves are really old...

Best Regards,