Live Database field titles appearing in square brackets [ ]

I’ve created a database, starting in sandbox mode.
Then I synced the database to live.
Then I realised that I had forgotten a field, so added this field in sandbox and then synced.
However, this field’s title appears in square brackets in the live database and when I add data to this database using code, it does not add this field’s data in live but it does in preview mode.

HELP!

Hi,
Your fields are not part of the schema. You can read more about it here .

Best,
Tal.