why does the jtag of Agilex™ 7 FPGA I-Series TransceiverSoC Development Kit recognize the wrongFPGA

You are right, different chip, I didn't notice. But same JTAG ID according to BSDL files nevertheless, so they can't be distinguished by autodetect, I fear.

attribute IDCODE_REGISTER of Agilex_AGFB027R24C : entity is
"0000"& --4-bit Version
"0011010000111011"& --16-bit Part Number
"00001101110"& --11-bit Manufacturer's Identity
"1"; --Mandatory LSB

attribute IDCODE_REGISTER of Agilex_AGIB027R31B : entity is
"0000"& --4-bit Version
"0011010000111011"& --16-bit Part Number
"00001101110"& --11-bit Manufacturer's Identity
"1"; --Mandatory LSB