I opened PR #919 that adds a @Disabled test to CDKAtomTypeMatcherFilesTest.

Irrespective of the meaningfulness of the chemical structure of the added file dativeBond.sdf the CDKAtomTypeMatcher throws a NPE with that structure due to IBond.getOrder being null when calling QueryAtomContainer.getMaximumBondOrder.

I don't have a concrete idea what should happen in this case, but throwing an NPE is probably not the best outcome... 🤷🏼