Markup macros prompt no longer popup the second time

Issue Summary

Adding Markup Macros into Confluence Page will popup the "Insert Markup" panel the first time and inserting another Markup, the popup panel no longer appears the second time for all browser. However, removing cache will reset the count and issue reappears. This issue happens to all browsers.

Steps to Reproduce

1. Create a new page (any type, tested on Blank)
2. Click on Insert More Content drop down menu

Expected Results

Markup popup panel appears

Actual Results

Inserting the Markup the second time will not show the "Insert Markup" popup panel

Error appears on the Console:

[Error] SyntaxError: JSON Parse error: Unexpected identifier "MARKDOWN"
	parse (atlassian-editor-plugins.d029127af5fa4a104e5c-v38.js:1:176019)
	Mn (atlassian-editor-plugins.d029127af5fa4a104e5c-v38.js:1:176019)
	(anonymous function) (atlassian-editor-plugins.d029127af5fa4a104e5c-v38.js:1:179932)
	execCommand (vendors~atlassian-editor.cf420a9674f38f58ca00-v38.js:1:27887)
	b (batch.js:508:511)
	(anonymous function) (atlassian-editor-plugins.d029127af5fa4a104e5c-v38.js:1:160984)
	(anonymous function) (atlassian-editor-plugins.d029127af5fa4a104e5c-v38.js:1:161102)
	dispatch (jquery-min.js:1:32141)
	a (jquery-min.js:1:27832)

Notes

The panel will appears for the first time on each Browser.
This issue might be interrelated with Markdown codes being rendered in Confluence Wiki format after inserting it on the page hence the error mentioned "Markdown": CONFCLOUD-65842: Markdown is saved as Confluence Wiki on the preview regardless of language mode

Workaround

- As a quick workaround, run browser in Incognito Mode or remove browser cache for "atlassian.net" to have the Markup popup once again.
- No permanent workaround at the moment