  We analyse the stability of the inner horizon of the quantum-corrected black
hole which is proposed in loop quantum gravity as the exterior of the quantum
Oppenheimer-Snyder and Swiss Cheese models. It is shown that the flux and
energy density of a test scalar field measured by free-falling observers are
both divergent near the Cauchy horizon. By considering the generalized Dray-'t
Hooft-Redmond relation which is independent of the field equation, we find that
the mass inflation always happens and the scalar curvature and Kretschmann
scalar are also divergent on the inner horizon. These suggest that the inner
horizon is unstable and will probably turn into a null singularity. The results
support the strong cosmic censorship hypothesis. However, this also implies
that the quantum corrected model may not be the definitive endpoint as a
regular black hole. Besides, it further proposes that it may be challenging to
observe the astronomical phenomenon which depends on the existence of the inner
horizon of the black hole.
