There's three questions about this problem, one of them is the answer:
a) the theory (QED) is incomplete and there's something that it cannot foresee;
b) the calculus are wrong;
c) the Rydberg's constant value is wrong .
 QED - Quantum Electrodynamics describes the interactions between light and matter and is one of the most successful in predicting the properties of atoms.
 The calculations are those who, from that theory, allow to calculate the size (radius) of the proton, one of the basic constituents of atoms.
 Rydberg constant whose value is also linked to the size of the proton.