Playlist - The good and the bad

grant_jenkins I have another issue which I have no explanation for. I wanted to modify the playlist template slightly which means modifying the JSON for the Thumbnail column. What I have found is that it is impossible to change the JSON but I don't know how changes are being blocked. For example, suppose I make an apparently minor change such as changing the letter "e" in the first "elmType" to "e". In other words I have not made a change at all. The list will now show "Something went wrong" and "Undefined is not valid JSON". Similarly, if I copy the JSON text into notepad or notepad++ and copy it back again without making any changes, the list displays the same error. Even highlighting all the text in the column formatting box, cutting it and pasting it straight back has the same effect.

I can't see any checksums anywhere so I don't know how Sharepoint knows that "e" is not "e" but there we are. I either use the template exactly as is or not at all. I should add that the playlist template works before I make any changes so its not that it is broken to begin with.