TableSync 'move' fails

In an updated 2013 (to 2016) database I'm having issues with a table sync upgrade. I've copied the original table to a new temporary table. Removed all code and variables from the new table. All fields are the same and so is the PK (even ran a text compare to confirm).

By my upgrade CU is throwing this error:

Sync-NAVTenant : When the TableSynchSetup.Mode::Move mode is used in an upgrade codeunit for synchronizing a table, the structure of the upgrad
e table must match the original table. The fields and the primary key of the upgrade table must match those in the original table.
The following errors must be fixed:
The definition of the upgrade table 'UPG-Extended Text Line' must match the definition of the old table 'Extended Text Line'.
Upgrade table 'UPG-Extended Text Line' cannot have fields which have a different design in the original table 'Extended Text Line': 'Text'.
At line:1 char:1

[TableSyncSetup] TableSyncSetup(VAR TableSynchSetup : Record "Table Synch. Setup")
DataUpgradeMgt.SetTableSyncSetup(DATABASE::"Extended Text Line",70500,TableSynchSetup.Mode::Move);

Any suggestions?