Support for Formula fields in batch campaigns was deprecated in 2013 and a notification was added to the product documentation here: Formula Fields. Currently, if a user attempts to schedule a batch campaign with an email that contains a formula field token WITHOUT spaces in the field name, the UI will show an error message saying this is not supported. However, due to an anomaly in the UI, if a user attempts to schedule a batch campaign with an email with a formula field token WITH spaces in the field name, the batch campaign will run. This UI issue was addressed in the January 2021 release of the product.
After March 19, 2021, these unsupported Formula Field tokens WITH spaces will no longer render correctly. Consequently, the tokens, and not the expected replacement strings, will appear in the final email. The deprecation is necessary to place all clients on a new, faster campaign processing platform. To avoid further issues we recommend migrating the Formula Field tokens to Email Script Tokens immediately. Please refer to the following article which discusses how to use this option: https://docs.marketo.com/display/public/DOCS/Create+an+Email+Script+Token
If you have further questions about this issue, and/or best practices on migrating to Email Script Tokens, please contact Technical Support. We want to ensure you have all the information you need to address the issue.
The team at Adobe