There are some relation problems between Iraq, Shingal, Syrian Kurd arrangements. (some connections to Turkey are a large part of it)
Syria Ping
Spanish Civil War had the same going on (on the Republican side).
At least early on there were multiple political party/union affiliated militias with foreign volunteers, that often got into trouble due to factional fighting. Orwell most famously, but many others too.
There was also political strife within the Communist-run International Brigades, which had political commissars, Soviet-style, who could and did conduct summary executions.