TinyMCE does not restore alt text and captions on figures

[iOvergaard]

Which Umbraco version are you using? (Please write the exact version, example: 10.1.0)

14.2.0

Bug summary

When you pick a media item and put in alt text and caption, and you then edit the inserted image, the fields are reverted to their defaults.

Specifics

The TinyMCE property editor.

Steps to reproduce

1. Insert a media item and give it a caption
2. Verify it inserts a <figure> with a <figcaption> in the source
3. Edit the image again, the fields are now blank / reset to default

Expected result / actual result

The caption field should be filled out with the stored caption. The alt text field, which is retrieved from the media item itself, should continue doing so unless the user has overridden the value.

[iOvergaard]

This is fixed by umbraco/Umbraco.CMS.Backoffice#2347 and will be released in 15.0.