Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/ARM/CMSDK_CM3/UART0/INTCLEAR#0x0
UART Interrupt CLEAR Register
TX Interrupt
RX Interrupt
TX Overrun Interrupt
RX Overrun Interrupt
https://github.com/cmsis-svd/cmsis-svd-data