Hello,
Thank you for your interest in our products
I would like to understand a little more about your setup, are you trying to access both interfaces (I2C and NFC) at the same time? Please keep in mind that this isn't possible, please take a look at AN12364 where it deepens into this feature. It is possible to mirror the memory into the SRAM or, to configure the NTAG 5 in pass-through mode.
Best Regards,
Fabian