Why would a simple page deleting in the CMS cause a Forge deployment to cause a catastrophic error?

I get a fatal error in Updater.php, and this on the deployment log

[Symfony\Component\Debug\Exception\FatalThrowableError]
Call to a member function in() on null

It took two hours of digging and deploying every commit hash until I narrowed it down to a few .md files deleted via CMS.

CMS changes shouldn't cause catastrophic errors in unrelated scripts with no real error messaging.