  QBism's foundational statement that ``the outcome of a measurement of an
observable is personal'' is in the straight contraversion with Ozawa's
Intersubjectivity Theorem (OIT). The latter (proven within the quantum
formalism) states that two observers, agents within the QBism terminology,
performing joint measurements of the same observable $A$ on a system $S$ in the
state $\psi$ 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 updating its principles.
The essential aspect in understanding of the OIT-impact on QBism's foundations
takes the notion of quantum observable. This paper comprises the complementary
discussion highlighting the difference between the accurate, von Neumann, and
inaccurate, noisy, quantum observables which are represented by PVMs and POVMs
respectively. Moreover, we discuss the OIT-impact on the Copenhagen
interpretation of quantum mechanics.
