I cannot get Dynamic Placeholders working in the content of email templates.  Whenever I try use a placeholder the result is that nothing appears.  I can add placeholders in the subject line manually but the manual ${} doesn't work in the content (email body) and the Dynamic Placeholder tool does nothing at all.

What are the steps to reproduce your issue?
1 - Create a new email template.
2 - Edit the Content (Body)
3 - Select Dynamic Placeholder using / and select Dynamic Placeholder tool.
4 - Choose any working variable and set or don't set default value.

What is the current behavior that you observe?
1 - The placeholder is not set and nothing happens after finishing with the Dynamic Placeholder tool. Test emails show nothing

What would be your expected behavior in this case?
1 - The variable or placeholder should be populated in test emails.


Notes:
1 - The placeholders work in the Subject when set manually. They don't work at all in the Content.
2 - I am using v16 with Chrome browser.