That you left Starter out would fall into my hypothetical category of "misuse."
That's why I'm not jumping to any conclusions.

If there isn't a "Use by" date on the boxes, the concentrates are stable.... Does Rollei or Tetenal or (liquid) Unicolor put "Use by" dates on their packaging?
The way-old Kodak Flexicolor liquid concentrates I have (just bottles, no box), do not have expirations on any of them. The Rollei Digibase home kits I've used before don't, either. I've never used Tetenal, and the only Unicolor kits I've seen have been powder, with no expiration. I'll be posting a picture of the bottles in the other thread referenced above in anyone's curious.