PAYE61070 | Employment maintenance: create employment: individual continues to be self employed
From HM Revenue & Customs · PAYE Manual
Taxpayers starting or changing PAYE employment may have a continuing source of self employment.
When starter information is received from an RTI employer and a primary employment is created, the SA record will link to the individual’s PAYE Service record unless
There is an outstanding SA work item
The taxpayer is subject to an SA enquiry
The SA record will move once the SA work item has been cleared or the enquiry has been completed.