The changes to the schema definition can be audited using the ACTION table in IncortaMetadata. We tracked the changes at the schema level, not at the table level. However, it is a best practice to schedule the backup of the tenant (all metatdata about schema, dashboard, etc) in your DEV env as well as in the Production env. It can be done by scheduling the backup from CMC. With the ACTION table and reports on the IncortaMetadata dashboard and the backup files, you should be able to identify the change made. Another utility available (upon request via support) is a tenant comparison tool, which can compare any two tenant backup and show the difference.
Hope this helps.