I don’t know that you can prevent it, but you sure can hide it or kill it
One “hide it” option would be to:
CRTPRTF TEMP OUTQ(TEMP)
RUNSQLSTM ... PRTFILE(TEMP)
and then periodically CLROUTQ TEMP
A “kill it” option would be to, in your CL program, simply DLTSPLF xxx SPLNBR(*LAST) where xxx is the name of your source member right after the RUNSQLSTM command runs successfully.