This is because the ‘Assessor’ parent role (which both Activity Assessors and Scout Show Assessors are variants of) has to have a generic setup within Compass, including the same training requirements. However, as we know, the variants of this role have slightly different training requirements: Scout Show Assessors are required to complete Module 25 Assessing Learning (Scout Shows), whereas Activity Assessors are required to complete Module 25 Assessing Learning (Adventurous Activities).
In order to work around this at present, when the PLP is automatically added you need to delete the module which is not required by clicking the ‘Delete’ button on the right hand side and then clicking ‘Ok’. More guidance on how to delete a module can be found here, and guidance on the training requirements for different roles can be found here.