Did you create automation in YAML-editor, or visual editor? HA is sometimes very picky about quotes, missing quotes, or incorrect quotation mark types to extent it drives one crazy. If you created automation in YAML-editor, try using visual editor, it’s actually very easy to use and helps avoiding errors. My guess is, error may have something to do with
data: {}
According to HA forums, it may have something to do with empty lines, this is maybe similar issue:
Message malformed: extra keys not allowed @ data[‘action’][0][‘message’] - Configuration - Home Assistant Community (home-assistant.io)