STPM33 SPI issue

I'm using an STPM33 digital signal processor driven by SPI using an STM32G071KBUX microcontroller. Comunication apparently seems to be ok but if I try to enable the only UART/SPI read error interrupt (into US_REG3 register) using the INT1 and INT2 as detection lines I see the following situation:

1) the INT1/2 lines go high but reading the flag bit 26 UART/SPI read address error it is 0, so an interrupt is serviced but no resulting flag is activated. WHY?

Different situation for other interrupts:

(bit 11) UART/SPI write error > (bit 27) flag: UART/SPI write address error

(bit 12) SPI CRC error > (bit 28) flag: SPI CRC error

(bit 13) SPI TX underrun > (bit 29) flag: SPI TX underrun

(bit 14) SPI RX overrun > (bit 30) flag: SPI RX overrun

enabled interrupts when serviced are correctly associated to their flags.