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In this article, we point out the issue of the first junction condition inthe Penrose diagram constructed by cutting and pasting analytically knownmetrics with spherical symmetry by a static spacelike thin shell. Wedemonstrate this issue by using two examples -- the generalized black-to-whitehole bounce with mass difference and the Schwarzschild-to-de Sitter transition.The goal is to construct the corresponding Penrose diagrams without anyexplicit or implicit illness at the thin shell. To accomplish this, we findthat two coordinate transformations are required unless a special condition ismet. The first transformation serves as the removal of the unwanted area whilethe second one reconciles the two different coordinate systems on two sides ofthe shell by removing an implicit discontinuity in the Penrose diagram of thistype. However, the second transformation brings a different kind of coordinatesingularity back to the event horizon. This coordinate singularity eithercreates a degeneracy such that all four-vectors are in 45$\degree$, or adegeneracy such that timelike vectors are parallel to the event horizon in theresulting Penrose diagram. We give geometric explanations for the discontinuityand this special type of coordinate singularity. We further show that no staticconformal coordinates can cover all of the event horizons without havingcoordinate singularity at some of them. Lastly, we draw a comparison to theReissner-Nordstr{\"o}m solution.

Trouble with the Penrose diagram in spacetimes connected via a spacelike thin shell