was this confirmed?

Based on provided photo that was also posted in iNaturalist. See link in description.

because Zacharczenko and Wagner ("A new cryptic Sympistis from eastern North America...") write:
“A Triosteum-feeding species of Sympistis is described from eastern North America: Sympistis forbesi sp. n. Identity of the new species is most reliably determined from larval morphology and host plant association—both adult scaling and genitalic characters overlap with those of Sympisitis chionanthi, a Chionanthus and Fraxinus feeder.”
“We were unable to identify any consistent genitalic differences in either the male or female genitalia that distinguish S. forbesi from S. chionanthi.”
“Although the adults of S. forbesi and S. chionanthi are difficult (and sometimes impossible) to distinguish even upon dissection…”
“We were unable to find consistent differences in male or female genitalia in S. chionanthi (representing five states and provinces), or between S. chionanthi and S. forbesi.”
“The adults of Sympistis forbesi and S. chionanthi are mixed in collections that we have examined (under the latter name).”

Maybe better to put it as just Sympistis then? Or is there a complex for them?

I see there is one a https://bugguide.net/node/view/1481920. Should I move it there?

And maybe something for fun? Look for larvae of either species.

Thanks for catching this. When I searched for Sympistis chionanthi I didn't notice that the guide item returned was forbesi.