UART data is corrupted when call occurs

I have STM32 board connected with main uart of ec25.
Then to send at commands via uart, I started
quectel-uart-ddp -uart /dev/ttyHS0 -smd /dev/smd8
code from command line. I can take response in idle state but when I started calling and checking CALL status with AT+CPAS, sometimes data comes corrupted with junk characters. Why this can be happend? Normally, I can communicate but when call occurs, UART is going crazy? How this can be solve?

Dear Ye110w,
Thanks for your inquiry in Quectel forum.
About your issue, i have some information need to confirm with you:

  1. you use Openlinux solution, not standard AT solution right?
  2. If yes, it is better to create the topic in the subject Open solution.
    3.If not, it is better to provide your test AT log, then we can help to check the reason.
  3. You also can use windows test log to check it.Thanks!