I have always understood a minority of O. triptycha lack the transverse dark bar admidships on the forewing. For exaple:- https://biocache.ala.org.au/occurrences/1fed8748-560d-4ae3-99ff-a17aa7ccad1e
Yes, on second thoughts I'm not sure this Olbonoma genus. It lacks the small 'tick' mark dorsally that o. tryptycha have, I have a vague recollection of seeing this moth before. Trying to recall....