I usually use the “Create deployment for this device” button in the device details to start a deployment. When I do so, the artifact selection dropdown list does not contain artifacts uploaded in my current web session. I have to logout and login again to be able to select the artifact.
I don’t recall if this applies to the artifacts list in the main screen as well. I’ll check the next time I upload an artifact.
Chromium Version 90.0.4430.212 (Entwickler-Build) built on Debian 10.9, running on Debian 10.10 (64-Bit) in case it matters.