We also want to underscore that all RNA samples were checked after extraction. Agarose gels electrophoresis confirmed the integrity of RNA and lack of DNA contamination.
It is known that HSA can bind RNA and DNA and has RNA hydrolyzing activity. In this way your experiment in par 2.2. may lead to not all RNA after incubation with such amount of albumin. That is why some of your effects may have other explanations.