The Imperial Russian Army (WW1), Western Roman Army (5th century), heck, George Washington almost lost the continental Army/Revolution (
and afterward) due to being unable to pay soldiers. MacArthur brutally killed many in the 'bonus expeditionary army' over money in 1932 (note; he was always an idiot and was reprimanded by Ike).
It has happened throughout history. The ancient tradition was to prevent it by allowing victorious soldiers to collect bootie as a reward, something essentially all of the Asian/European empires permitted including both Roman ones. There's not anything left to allow the IRGC to plunder though.
The IRGC would absolutely turn if unpaid, to say
nothing of the Shia Arab mercenaries they have desperately brought over the border because the basij and IRGC themselves couldn't quell the uprising.
Separately (Alaskanag99) yes, Line in the Sand did discuss
Sykes-Picot treaty of 1916 apportioning the Kurds to live within 5 separate states, functionally making them powerless. There was more discussion of this 10 years or so ago I think, or before Obama gave up on/rejected negotiating a status of forces agreement in Iraq. Today, I think the Turks, Syrian 'government,' Iraqi's alike vehemently oppose 'fixing' this historical situation, to say nothing of the mullahs. There are zero 'easy' answers to that dilemma.