Hello,
I came across a problem while adding title data. I tried adding data in my test title, which doesn't have any title data, and the page gave me error. It gives the same error even if there is some data. Uploading JSON file to update the data works though.
Also, I don't know if there was an option before but I cannot see override Title Internal Data option on the page. For Title Data, the override button appears when there is data.
(TestKey in the image was added by a JSON file to test if uploading JSON works)