YAML files aren't intentionally excluded from bundle sync, so this is almost certainly a config or snapshot issue rather than a product decision.

A few things to check:

1. .gitignore is the most common cause. Bundle sync respects your .gitignore by default. If your repo has *.yml, *.yaml, or specific config file patterns listed there, those files will be silently skipped during bundle deploy even though .py and .sql files sync fine. Check your .gitignore (and any nested .gitignore files) for yaml-related patterns.

2. Direct remote edits corrupt the sync snapshot. You mentioned you're editing config YAML directly in the workspace during dev. The sync uses a local snapshot to track what was last uploaded. When you edit a file remotely, that snapshot doesn't update. Next time you run bundle deploy, the sync compares your local file against the snapshot. If the local file looks unchanged from the snapshot's perspective, it skips the upload entirely and leaves the remote as-is. This can make it look like local YAML changes aren't making it through.

To force a full re-sync and break out of this state, run:

databricks bundle deploy --full

3. Going forward, treat bundle deploy as the source of truth for your workspace files and avoid editing remote copies directly. If you need to iterate quickly on config, edit locally and either re-deploy or use databricks bundle sync --watch to continuously push changes as you save.