Yeah, those are screaming "first year plants."
https://www.thespruce.com/virginia-swee ... or-2132731
While The Spruce is sometimes a little questionable in terms of advice, this is pretty much spot-on. Sweetspire is a semi-evergreen, and yours are young and trying to stay awake. Given the winter so far (not very harsh), that's about what I'd expect.
The reds are produced by anthocyanins:
https://en.wikipedia.org/wiki/Anthocyanin
If you check the article (which is laughably oversimplified, but let's run with it), anthocyanin is produced by plants when fall comes in response to environmental keys. Your plant simply didn't do it last year. That's not unusual for young plants, plants that haven't adjusted to their local environment yet (recently planted plants, even if not young), or plants that didn't have time to adjust to fall (sudden weather changes). Tricking your plants, the way I do, will also cause them not to change color and instead go from green to dropping leaves.
An anthocyanin is nothing but a glycos...look, this gets complicated. There's nothing magic about the molecule, it's made of carbon, hydrogen, and oxygen. Nothing else. If you're curious:
https://en.wikipedia.org/wiki/Anthocyanidin All this is available from the air (carbon) or water (hydrogen, oxygen).
Feed 'em correctly next year (in spring, summer, and early fall) and they should do just fine unless the weather where you are would lead them to be more evergreen, and keep them toward the damp side. A soil test might be in order, but these are not particularly touchy shrubs.
