Received one of these at the weekend for an employee who we have not been deducting PG loan payments but have been deducting Student Loan payment. Just rang the HMRC helpline and the advisor said I was the third call she had had this morning saying the same thing and told me to ring the SL helpline. So it looks like HMRC have messed up somehow.
I just rang the number for the SLC that HMRC gave me (0300 1000611) but they are not accepting calls due to Covid.
I think I will just wait and hopefully HMRC will send a correction notice.