If you added the employee as a new starter and you selected the pension scheme in the new starter screen, this can cause issues with Sage 50 Payroll as this tells the software that you are manually adding the scheme and this overrides the autoenrolment process for the employee and can cause issues with opting out, etc.

If there is no pension scheme added to their employee record then technically no calculations for pension can be made so I would leave it as it is and see if the pension calculates on your next pay run.

If you added the employee as a new starter and you selected the pension scheme in the new starter screen, this can cause issues with Sage 50 Payroll as this tells the software that you are manually adding the scheme and this overrides the autoenrolment process for the employee and can cause issues with opting out, etc.

If there is no pension scheme added to their employee record then technically no calculations for pension can be made so I would leave it as it is and see if the pension calculates on your next pay run.