I encountered the same issue. repoName is devcontainer_demo, "/devcontainer new_a" clone to ~/.local/share/opencode/clone/devcontainer_demo/new_d.

--workspace-folder is used as ~/.local/share/opencode/clone/devcontainer_demo/new_d, and the path in the created Docker container is /workspaces/new_d.

In override-config, workspaceFolder is the repo name, that is, devcontainer_demo.

The error log in jobs.json is as follows:
OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused "chdir to cwd (\"/workspaces/devcontainer_demo\") set in config.json failed: no such file or directory

I am not very familiar with devcontainer. I asked opencode to help me locate the fault. The explanation is as follows:

The devcontainer CLI reads the workspaceFolder field in override.json.
The CLI translates the value into docker exec -w /workspaces/devcontainer_demo...
The dockerd generates an OCI runtime spec for this exec and writes it to config.json.
(The cwd field is "/workspaces/devcontainer_demo".)

I am not sure whether this is correct or whether it is related to the DinD deployment. (I started the docker daemon in the Kubernetes pod and executed opencode /devcontainer.)