RUN command is not supported in cache probe mode

I am using the envbuilder terraform provider to cache my workspace image in coder.
Could somebody help me understand why I always see the following error which results in a cache miss?

> Failed to find cached image in repository "myrepo.org/coder-ssd-local-storage-nvme-test/coder-494b6612-e6be-42e1-b653-969164b30b53". It will be rebuilt in the next apply. Error: get cached image: error probing build cache: uncached RUN command is not supported in cache probe mode

Are there devcontainer elements that cannot be cached such as devcontainer features?
Or what does "uncached RUN command is not supported in cache probe mode" mean?

Reproduce the cache miss with the envbuilder Terraform provider and the reported devcontainer configuration, then trace the cache probe path that emits “uncached RUN command is not supported in cache probe mode.” Determine whether devcontainer features or other RUN commands are intentionally unsupported, and document the behavior or define the needed change.

Written by the indexing model from the issue text.