atom has no _residue

[mizuchi3]

Ok, this is a weird template, but https://swissmodel.expasy.org/templates/5w7n.1

I make a selection on rnames, and for this structure specifically DC and DG cause the problem.
var dna = pv_structure.select('ligand').select({'rnames':[ 'DA', 'DC', 'DG', 'DT' ]});

later, If I try to either make a cartoon or trace representation, or make a ColorOp, PV throws an error that atom._residue is undefined.