I have the same issue, would be great to get some help as to why it’s not visible.

@Joël Kemnitzer  / @Ben Jennings - I do not see this field either, but I have also never looked for it, so I am unsure if it was ever available/was available and was removed/is no longer supported/there is a bug/etc.

Upon review of the Jira Cards help center article, I see:

If some fields are not displayed on the board after you chose them in the picker, it means that:

• a field doesn't have a value to be displayed on the board
• this field is not available for the issue type (e.g.Epic name field is available to Epic issue type only)

If you can't find a field on the card fields list, it means that:

• that kind of field is not supported by Miro (e.g. color type custom field)
• the field is not associated with your Jira instance. Please see the Atlassian guide for Configuring custom field contexts for more information. Please read Possible issues with Jira cards and Jira add-on.

Source:

https://help.miro.com/hc/en-us/articles/360017572434#Enabling_custom_fields_on_Jira_Cards

And in the Jira Cards FAQ:

Are custom Jira fields supported?

Yes, we support almost all custom fields of basic types. If you have a complex data type field, it may not be supported and cause unexpected behaviour when updating or creating Jira cards on the board.

Source: https://help.miro.com/hc/en-us/articles/360013463739

Asking Miro Support

I would suggest that you ask the Miro support team for an official answer by opening a support ticket:

https://help.miro.com/hc/en-us/articles/360020185799-How-to-contact-Miro-Support#h_01F010RXA0E1S9C0WFQYX75R6C

If you do open a ticket, I would suggest that you

• please update this post with what the support team tells you
• ask them to add the list of supported fields to a help center article to avoid users having to wonder what fields are supported or if they aren’t showing up, is it a bug or expected. 

OK thanks Robert, will do!