Mhamad Hantro thanks for your answer, I did do this work but the problem persists, I changed the CHK name and used fchk keyword and got test.fchk again in the scratch file.
Massimiliano Arca Good idea Professor, as you know when we run the Gussian with fchk keyword we get test.fchk file in the scratch folder, when we run multiple tasks in Gussian we only get 1 test.fchk file, in case we need all fchk files related to our tasks (Because the name of all of them is the same and cannot be changed). but I think the only thing that can be done is your suggestion, converting chk to fchk. and I think Gussian needs to fix this problem.