The SMILES COC(=O)c2ccc3n([H])c1ccccc1c3(c2) which
contains a 6-5-6 fused ring system (pyrrole being the
middle ring) is incorrectly displayed by JChempaint
which would indicate an error in the parsing.
Rather than treating the pyrrole ring + H attached to N
as aromatic, it appears to ignore the H and simply
attach it to the N, which results in a wrong valency for N.