I've been running an automation workflow with Mailchimp for a while, which has a simple welcome Newsletter. The Automation email editor only lets me edit the HTML version of the email, and auto-generates a text-based version.
However, it only generates the plain text version when the email is first created. I have edited the HTML version several times since then, and only just realised that the plain text version is still stuck at its initial state. I can't find any way to edit that plain text version, or even to disable it!
MailChimp has updated the process: 1. Pause the entire workflow, 2. Go to the 'confirm' screen 3. 'see details' of each individual email 4. 'edit' plain text version 5. click the (extraordinarily well-hidden) 'regenerate from HTML' button 6. restart the entire workflow
Click on the automation, then click on the "confirm" step at the bottom of the page. Scroll down a bit and under the "Emails" heading, click "Email details" next to the first email in the workflow. Scroll down a bit and there is a section labeled "Plain-text email". Click "edit" next to this, then click "regenerate from HTML". This will repopulate the plain text version with any updates that were made to the HTML version. Click "save" to save the change, then repeat for any other emails in the workflow experiencing the same problem.