Clicking 'Resume Edit' while Collaborative Editing off causes HTTP 400

Issue Summary

This is a continuation of the bug CONFSERVER-93655 - Getting HTTP 400 while saving page by using the close button..

The same issue occurs in a specific scenario. I described the behavior in the 'Steps to Reproduce' section.

Steps to Reproduce

Scenario 1

1. Create a fresh instance with Confluence 8.5.5 (or 7.19.18)
2. Turn 'Collaborative Editing' off.
   • Navigate to the General Configuration > Collaborative editing > Change mode and select 'Off'.
3. Create test space
4. Create a test page
5. Insert ../ to the page and save it
6. Then edit the page again, add new regular content, and click Close.
7. Go to the edit mode again, and the below pop-up will be displayed:
   
8. Click 'resume editing'

Scenario 2

It also happens incase ../ is added as content in the blog or comment

Scenario 3

This issue is also reproducible when a child page is created for the parent page with ../ in the Page Title :

• Create a Parent page with a Title containing "../" like the title of the page can be "ParentPage../"
• Create a child page for the parent page and add content.
• Either close the Page using the Close option or Save the Page post which an HTTP 400 error is observed for the "docreatepage.action" call.

Expected Results

The editing or saving process should function properly.

Actual Results

Getting HTTP 400 message:

Workaround

Scenario 1

You can use 'view the change' on the same pop-up to copy your changes and discard the draft. After this, you can edit the page and 'Save' using the noted changes to prevent this issue from occurring again.