Change of job profile before i140 filling

I am in a situation and worried. My employer has filled a perm for engineer role with client A for me. While the perm was in process the client position was lost and then I had to take up other role within same employer. The new position is technical PM.
Just before the perm approval they extended my H1b and new H1b is now for PM role. I have just got my perm approval for the previous role. I am proceeding with filling i140 with the same perm. I am worried what will be the effect because of role change before i140 filling. I have only 4 months left to maxout my H1b 6 years so no time for perm again.
Any advise or will that matter once perm is approved?

First off all, PERM/GC is a future job and it can be different from your H1B job. As far as your employer is able to offer your the PERM job, able to pay PERM wage, the job is in line with your education, skills and experience, there should be no issue.