Video support for Custom Publishing HTML column

We have sharepoint on-premise and online setup. We have a custom list and a site column of type Publishing HTML (Full HTML Content with formatting and contrarians) is added to this custom list. https://i.stack.imgur.com/ruYrX.png

All the text based and HTML based content get successfully saved in the list. However, whenever video is inserted (from computer/ from sharepoint) it does play in the preview but once item is saved video code gets lost (iframe) (See edit snippet)

https://i.stack.imgur.com/7hkeq.png

Same video works fine for multiple line of text column of type enhanced rich text editor .

we already have solution in production so cannot change column type at this stage. We tested this in both environment and cannot get it working.

Has anyone seen this issue?

NOTE: OOB Publishing HTML column created by sharepoint (e.g. page content) works fine and can play same videos. Just custom columns are having issues