Given there’s a corp of scientists, why do you think this is the case?
It’s clear the Nodong first stage is the problem probably even affecting the 3rd stage in not giving enough altitude for insertion. Hence why Safir-3 (Zuljanah) is moving away from the first stage.
I think there is competition between IRGC and Iran space agency. They helped build Simorgh and then Rouhani delayed Simorgh launch over and over. Created a rift between the two organizations. Second of all, Iran space agency is a den of spies. Tough for IRGC to trust the people there.
If Iran supplies sensitive missile stages to ISA, guess what they also have to supply? Data on the stage and specifications. Guess where that data ends up? In hands of Israelis and US where’s it fed into supercomputer models to guess the remaining missing pieces of Iran’s BMs and help their interceptors better understand Iranian missiles to intercept.
Lastly I do think there is a lot of sabotage in the ISA either by people against the Republic or paid agents or both.