QBism’s foundational statement that “the outcome of a measurement ofan observable is personal” is in direct contradiction with Ozawa’sIntersubjectivity Theorem (OIT). The latter (proven within the quantummeasurement theory) states that two observers, agents within the QBismterminology, performing joint measurements of the same observable A on asystem S in the state ψ should get the same outcome A = x. In Ozawa’s terminology,this outcome is intersubjective and it can’t be treated as personal.This is the strong objection to QBism which can’t survive without updatingits principles. The essential aspect in understanding of the OIT impact onQBism’s foundations takes the notion of quantum observable. We discussthe difference between the accurate, von Neumann, and inaccurate, noisy,quantum observables which are represented by the projection valued measures(PVMs) and positive operator valued measures (POVMs), respectively.Moreover, we discuss the OIT impact on the Copenhagen interpretation ofquantum mechanics.