  K2-19 hosts a planetary system composed of two outer planets, b and c, with
size of $7.0\pm 0.2~R_\oplus$ and $4.1\pm0.2~R_\oplus$ , and an inner planet,
d, with a radius of $1.11\pm 0.05 R_\oplus$. A recent analysis of
Transit-Timing Variations (TTVs) suggested b and c are close to but not in 3:2
mean motion resonance (MMR) because the classical resonant angles circulate.
Such an architecture challenges our understanding of planet formation. Indeed,
planet migration through the protoplanetary disk should lead to a capture into
the MMR. Here, we show that the planets are in fact, locked into the 3:2
resonance despite circulation of the conventional resonant angles and aligned
periapses. However, we show that such an orbital configuration cannot be
maintained for more than a few hundred million years due to the tidal
dissipation experienced by planet d. The tidal dissipation remains efficient
because of a secular forcing of the innermost planet eccentricity by planets b
and c. While the observations strongly rule out an orbital solution where the
three planets are on close to circular orbits, it remains possible that a
fourth planet is affecting the TTVs such that the four planet system is
consistent with the tidal constraints.
