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TRF7970A: Getting RX IRQ but no data

My init & register settings:

sendDataToTrfWithOneByteOpcode(0x83, 0, 0); // Reset
sendDataToTrfWithOneByteOpcode(0x80, 0, 0); // Idle
write_trf_register_value(0x09, 0x01);
// Write&Read Modulator and SYS_CLK Control Register (0x09) (13.56Mhz SYS_CLK)
write_trf_register_value(0x01, 0x88);
// Configure&Read Mode ISO Control Register (0x01) to 0x88 (ISO14443A RX bit rate, 106 kbps) and no RX CRC (CRC is not present in the response))
write_trf_register_value(0x00, 0x21);
// Turn RF ON (Chip Status Control Register (0x00)), 5V operation

sending REQA packet:

getting TX IRQ, clearing it, clearing FIFO:

getting RX IRQ, clearing it, getting 0 bytes in FIFO status register, clearing FIFO:

then a few ms later I get an IRQ (0xC0) when I'm trying to send a new REQA:

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