Autosave-like environment versions?

I am trying to use a custom environment (docker-based) within a PythonScriptStep. The environment exists (version=1) in the workspace and has already been successfully built with Docker (build status is succeeded).

Whenever I try to run the pipeline and use this environment AzureML ignores the environment version and injects a version named `Autosave_{YYYY}-{MM}-{DD}T{HH}:{MM}:{SS}Z_{some_hash}.`. The pipeline run then fails saying this version does not match the one provided (version=1). This environment version then appears in the environment versions list but I did not create it. There are no builds available for such environment version.

Is this expected? What might be causing this?