Yes, so I did test a few scenarios now.
Guest User A is added to a task as a follower in project B.
Guest User A will be able to edit the assignee, due date, subtasks, etc but he won’t be able to edit the custom fields or see them, apart from the ones that have something selected but then it will show as locked
This is what I (as a full org user) see:
This is what the guest user sees:
Now I am assigning the task to the Guest User A
This is what the guest user sees now:
The custom field section looks the same but the user can now delete the field and value from the task.
Now I am adding the Guest User A to project B with comment access.
This is what Guest User A sees when they are a follower of a task within the comment only access project B:
And this is what Guest User A sees when they are assignee of a task within the comment only access project B:
They will now be able to make changes to custom field selections.
Now if Guest User A reassigns the task back, this message will pop-up
Then the guest user will have the same access as per above screenshot (comment access only)
I understand where you are coming from regarding it being confusing that users have more access to a task within a project they only have comment-access only too, but as far as I understand this has to do since the task then also shows in their My taskx and then the task access applies.
Ok so for this yes it is correct and indeed a bit weird that they can add subtasks if they are just collaborator of a task but once they get comment only access to the project they cannot add them unless the task is assigned to them.
Might also have to do with the fact that before the task shows to them as if it would be a standalone task (as they don’t even see the project it belongs to) but yeah I agree this can be a bit confusing indeed.