In Kurdish dictionaries, the Arabic loanword قربان (qurbaan, from Aramaic) is spelt “qurban”, just as in Turkish (technically “kurban” in Turkey and “gurban” in Turkmenistan, although “qurban” in Azerbaijan). In Tehrani Persian, all occurances of the vowel “damma” (actually “ضمة” is pronounced 9’amma in Arabic and Persians call it “پيش/pish”, although that word means “front” and is pronounced “pêsh” in Afghanistani Persian and in Kurdish, hence “pêşmerge”, not to be confused with “peş” in Turkish, which means “back” and descends from a dialectal pronunciation of the Persian “pas”) are pronounced “o”, thus “qorbån”.
The fact that Turks use the same vowel as Arabs in this case is unsurprising because unlike Tehrani Persians, who only have six vowel phonemes (and thus more or less automatically assign their vowels to conform to the short and long Arab ones in long words), almost every Turkic variety has too many vowels to have such an automatic assignment, and so Arabic loans can be dealt with seperately from the native vocabulary in terms of vowel patterns (and in some cases consonants). Even standard Uzbek, which in theory has only six vowel phonemes, has no trouble rendering both 9’amma (mumkin) and waaw (mazlum) as “u”, reserving “o'” for Turkic vocabulary (Persian vocabulary spelt with a 9’amma is realised as “u”, just like in surrounding Persian dialects), even though back when they used the Arabic script (not long ago), both were rendered with a 9’amma (as was the “u” in qurbon, of course). Their Turkishness shines through their Persified vowel inventory.
The Kurdish case is similarly straightforward: Kurmanji (like Afghanistani Persian) has 8 vowel phonemes (a e ê i î o u û; Afghanistani Persian, for the record, counts a å e ê i o ô u), so there are two short rounded vowels which can replace 9’amma. Officially, Kurds say “u” because that’s the Arabic way, and it’s an Arabic word.
Meanwhile, in Kars:
Kars is a city with a mixed population of Kurds and Turks. Bilingualism is common as Turkish is the state language of the Republic of Turkey and not learning Kurdish would put local Turks at a significant disadvantage when Kurds tell dirty jokes. But there are still some ways to tell who is a Turk and who is an Aryan. One of these is the word “qurban” mentioned above. Kars Kurds pronounce this word “qorban” in both Kurdish and Turkish, while local Turks switch the “u” for an “o” only when speaking Kurdish. It is interesting to see that although Kurdish nationalists have assigned a distinctly Arab accent to this word in the new standard language, and although they have lived for years in the Turkish Republic, and their neighbours to the East consist of Muslims of various nationalities who ALSO render the first vowel of this Arabic word “u”, the Kurds of Kars (“Qers” to them) insist on a Tehrani Persian pronunciation to this day. Supporters* of the political idea of “Pan-Iranism” ought to hail this as a victory.
*The link from the English homepage to the Persian homepage is marked “بخش پارس”, although almost all references to the language on the Persian site say “فارسی”.