Please tell me, why do the two models 5M1270ZF256I5N and 5M1270ZF256C4N appear on the same chip?

Hi,

Thank you for contacting Intel Community.

Please note that dual part markings on MAX® V devices are intended to show -4 commercial specifications also meet the -5 industrial specifications.

Refer to our KDB: https://www.intel.com/content/www/us/en/support/programmable/articles/000079006.html

Regards,

Aiman