Hi Again !
As you mentioned, I’m not planning to switch to new theme, I have to go through lot of content migration. If there is nothing could be done with my current theme, I’d let this go away. I have added more information about the issue below.
My theme was working fine with Gist block, because I’m using it for nearly an year and Gist block was working fine too. This issue happened like a month ago, and it didn’t happen because of updating theme, since there was no update for it for so many months.
Site – https://developersbreach.com
Posts using Gist blocks – https://developersbreach.com/drag-to-reorder-compose/
Notice that gist block was used in that above post was created 2 months ago and it was working fine.
Now in my editor the block won’t behave same.