Questions & Answers about این اشتباه تصادفی نیست، بلکه تقصیر مدیره.
How does balkeh differ from vali or ammā (but) in this sentence?
balkeh translates to "but rather" or "on the contrary." We use it specifically because the first clause is negative (nist - is not) and the second clause corrects it by offering the true fact. You use vali or ammā just to add contrasting information, not to substitute a negative statement.
How is the word tasādofi (accidental) formed?
It comes from the noun tasādof, which means "accident" or "coincidence." Adding the suffix -i to the end turns the noun into an adjective, making it "accidental."
There are two "e" sounds in spoken taqsir-e modire. What do they both mean?
The first one is the ezafe connector linking "fault" (taqsir) to "manager" (modir) to show possession (the manager's fault). The second one at the very end of modire is the colloquial spoken short form of the verb ast (is).
Do we have to include the verb at the end of the balkeh clause?
It is very common to omit the verb in the second clause if it is the same as the first one. Here, the speaker chose to include the colloquial verb -e (is) attached to modir, but saying balkeh taqsir-e modir without the final verb would also be perfectly natural.