`o3` / `o4-mini` Restore Markdown Formatting

Anyone figured out how to restore Markdown formatting on the o3/o4-mini models released today?

For o1, the docs pointed to prepending “Formatting re-enabled” to the Developer message.

Despite prepending “Formatting re-enabled\n” at the beginning of the request, o3 and o4-mini output flat text.

Example below:

This seems a regression in behavior? Or maybe there’s a different way to turn formatting back on?