Attachment Thumbnails not created for Docx and PDF and prevents switching attachment link to show as thumbnail

Summary

When uploading a .docx file or PDF file onto page, it defaults to being set to display as a thumbnail, however the thumbnail is not generated. To make the page look better, you can switch the attachment to "Show as link". Once this is done, if you attempt to change the link to "show as thumbnail" the "close" button of the editor will grey out and the publish button will no longer function.
Leaving the page does keep changes in the draft.

Environment

Cloud

Steps to Reproduce

1) Create any Docx or PDF file and upload it onto a page by drag-and-drop. This will set it to display as a thumbnail.

2) Hit publish to see that the attachment is now displaying a small placeholder thumbnail indicating that the thumbnail was not able to be created or loaded.

3) Edit the page again and set the attachment to display as a link. Publish the page.

4) Edit the page again and try to change the attachment to display as thumbnail.

Expected Results

The thumbnail is generated and displayed and the editor is able to save.

Actual Results

The Editor is not able to save and the close button is greyed out as if no changes were made to the draft.

Notes

=== View As Thumbnail ===

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=== After Hitting View As Thumbnail ===

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=== Example Of Thumbnail ===

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Workaround

There is currently no workaround for this, however you can close the editor page and re-edit the page to post any other changes that you have made to the page.