US 412 is less compliant than I-155 meeting another interstate at it's far end, surely? There's bag loads of precedent for 3dis that are odd as they don't join back to their parent route or any siblings (plus other ones that do 'keep it in the family').
I-135 (KS), I-155 (IL), I-170 (MO) - another that the route at the far end became interstate later, I-195 (RI-MA) - meets a sibling at far end, I-196 (MI), I-335 (KS), I-355 (IL), I-376 (PA), I-380 (PA), I-390 (NY) - far end became interstate later, I-395 (CT-MA), I-505 (CA), I-520 (GA-SC) - meets parent at both ends, I-580 (CA), I-590 (NY) - meets siblings at both ends, I-780(CA) and I-980 (CA) - meets two siblings.