Unable to update HTML Markup Custom button

Summary:

Content (please ensure you mask any confidential information):

We have a custom button inside the Worker Goals page. We have to update the script inside HTML Markup since we'll be attaching a profile option instead of a hard-coded link (the purpose is so whenever we change/update the link for the button, we don't need to go inside a sandbox and update it). However, just like what others experienced - part of the script gets missing after clicking Apply in Page Composer.

We are aware of the known issue in HTML Markup functionality in Page Composer. However, we badly need to update the custom button that was created using HTML Markup. The workaround that was mentioned in Document 2706327.1 doesn't seem to work on buttons or maybe there's something I missed?