T0 - You Validate a package to PROD (run all tests)

T1 - You or someone else does a deployment of something else, no matter how minor, to PROD.

T2 - You click Deploy of the Validated Package from T0, all the apex tests are rerun. This is by design per SFDC yet Gearset doesn't tell you in advance that Quick Deploy is not available. Something you think will take a couple of minutes now takes 30 minutes or more. You think you screwed up or Gearset is broken

Suggestion: On Validated Packages page and on the page of a specific validated package, display a warning that a subsequent PROD deployment has occurred since the package was validated and that Quick Deploy is not available. This will help set expectations.