Civ listed friendly with you, but refuse to trade tech/open borders/trade resources with excuse "We just doi not like you enogth".
Happened if civ does not like your vassal. It does not matter if that civ is your vassal or not.
Way to reproduce:
Get Vassal, Get other civ to friendly but do not like your vassal.
Happened if civ does not like your vassal. It does not matter if that civ is your vassal or not.
Way to reproduce:
Get Vassal, Get other civ to friendly but do not like your vassal.
