Viva no longer providing schedule send options

In Outlook (desktop, classic) Viva prompts to suggest scheduling emails at a good time, as illustrated below, which is great.

Previously, clicking "Schedule send" opened a Viva panel that let you confirm the time at which you wished to schedule the send. Now, however, the panel opens with a bunch of irrelevant options and no option to schedule the send:

How do I now get Viva to actually schedule the send for this email?

Thanks