Extension rejection scheduled after being approved, now has been reverted to version from 2019

What is going on? Is this some automation failure?

Looks like everything worked as expected, the initial approval says

Keep in mind that other reviewers may look into this version in the future and determine that it requires changes or should be taken down.

So a human reviewer looked at the sources you provided and tried to build it. However building the sources you provided failed for them, so they asked you to ensure they can build the extension from the source you provide. To which you seem to not have reacted for 14 days and now automation rejected the version, since there’s no way to verify the source code actually represents what’s in your XPI. Leaving the version would essentially mean an extension that can’t be security reviewed is available forever.

Understood. But the reverted version is from 1 year ago and doesn’t work with our current api…

Its like suddenly, all previous version were automatically checked, and marked for rejection

Actually a version from 2019!