MISRA checker wrong Inferring after passing pointer to function

Somewhere in my project I have this code:

  {
    uint8_t u8Integer = 0xFFU;
    returnCode = someFucntion(&u8Integer); 
    uint8_t u8Decimal = 0xFFU;
    returnCode = someOtherFucntion(&u8Decimal);

    uint16_t u16Temp = ((static_cast<uint16_t>(u8Integer) << 8U) | static_cast<uint16_t>(u8Decimal));
      if(u16Temp <= 0xC000) // Problem here
      {
        // Uneracahble Code ?
      }
      else // {...}
  }

An automatic MISRA static check throws an error saying that the if statement is never true. I guess Is because the u8Decimal and u8Integer are modified when passing their pointers to someFucntionand someOtherFucntion and the checker assumes they are still 0xFF and therefore u16Temp will never change making it alwas > 0xC000 .

When I run this program, the values of u16Temp change properly (sometimes entering the ifstatement and nometimes not).

the checker says "The inferred value of u16Temp is 65535"

Is this just a case where the checker is not working perfectly? Or do I actually have a code problem?

I tried setting the variables as volatile but this didn't work.