Custom Confluence templates are not displayed in the new "Create Confluence pages without leaving your Jira issue" feature.
Recreating the Bug
- Ensure you have a custom Confluence page template in the applicable space.
- Open a Jira ticket, click 'Create', then select 'Page'.
- When a dialog appears, select the Confluence Space in which your custom Template resides, and click 'Create'.
- The new Confluence page will appear over top of Jira. Under Templates, on the right of the screen, custom Templates are not displayed.

Image 1) Custom templates not displayed when creating Confluence pages in Jira.

Image 2) Custom templates displayed after opening the page in Confluence.

Image 3) "You don't have any custom templates" when creating Confluence page in Jira.
Workaround
- In the top left of the screen, click 'Open in Confluence'.
- When the Confluence page opens, at the top right of the screen, click the 'More actions' dots, then select 'Templates & import doc'.
- Your custom Templates are then accessible.