so, what is more likely-
1- thousands of academic researchers who use PCR never noticed the limitations.
2- some Tanzanian despot deliberately contaminated a three samples so he had an excuse to kick out WHO.
Yes, despot. Only one ruling party since 1962. In case you wonder about their medical expertise, Tanzania is also the world leader in muti, the practice of hunting albino human beings for their body parts for use in medicine.
So, your source is the despot ruler of a third world country where humans are killed for use in magical potions.
Dang. You sure can pick them. That is a source of unparalleled credibility.