When neither Max Versions nor time to live (TTL) is configured, each row stores only the column name and data value.
Configuring Max Versions or TTL switches Tablestore to a multi-version storage model. In this model, a version number serves as the index key that identifies each cell version. Without it, Tablestore cannot distinguish between versions or enforce expiration. As a result, each version stores an additional 8-byte version number alongside the column name and data value, which increases the overall table size.
This is expected behavior, not a sign that something went wrong. The size increase scales with the number of versions stored per row.
For more information about Max Versions and TTL, see Data versions and TTL.