I have created a new module to add some bespoke behaviour to projects for our company. The field works in all my internal views without issue. I can also view it in the model for project.task. When i try to add it to a portal view using the code below I get some strange (to me anyway) behaviour.

(sorry tried using the code box but it kept re-formatting it all in an un-readable manner)

How it appears as an internal user viewing the portal (This is the desired behaviour for all portal users)

Error visible when trying to view the project views as an external portal user (i.e. not an official internal user, just invited via email like you would with a partner/customer)