Unable to save template with Insert Markup

Issue Summary

This is reproducible on Data Center: (yes)

Steps to Reproduce

1. Create a new template:
Click on "Create New Template" under Space tools.

2. Click Add Insert Markup object from Other macros.

3. Copy the markup from the existing page using the source editor plugin.

4. Go back to the template creation and Insert copied markup --> Click on Insert

Expected Results

Markup is added

Actual Results

We see the error confluence.conf_wikimarkup_conversion_errors. Request failed with 400

Workaround

Steps:

1. Create a template and save an empty template with just a template title.
2. Install the source editor app.
3. Edit the saved template and "Open in source editor"
4. Insert copied markup in it
5. Save the template.