Block Transaction DB to OPC no write if DB table & PLC size are not the same

Using v.8.0.10, I have a view in MySQL, currently it returns 8 rows. I have a block transaction group that is DB to OPC, the OPC data size is 20. If I set the transaction group size/length to anything larger than the view row length, no OPC writes will occur. No errors, just no writes. Once I change the size/length to 8, it will start writing. Is this normal behavior?