Webapp Builder - Threat Analysis Widget user permission issues

[Spatialelement]

I've built a webapp which includes a Threat Analysis widget with a set of custom buffers configured. The buffer results need to be published to an existing Published Layer by my users. My user is a "Mobile Worker" user type and "Data Editor" role. They are able to edit the layers within the webapp using the standard edit tools, it just seems to be that publishing the outputs from this widget are not permissible. Any help would be appreciated. Screen shot of their error below.

They Assessment Buffers target layer is editable in the feature service settings.