728 Part Marking on ATTiny414

I had a customer send an a email letting us know about the parts that he bought.
He wanted to share this information with us.

The Attiny414 I purchased from DigiKey have the following markings on them.

Atmel 728B TK
TINY414-F
A3NASB

These units do not have temperature sensor calibration data loaded onto them and therefore the internal temperature sensor is not useful.

I was told by Microchip support that the 728 marking means they are engineering samples and do not have calibration data loaded.