Follow-up Fall-down

We have noticed that sometimes the follow-up wizard will not allow you to assign the activity to someone else. You must open the activity and change the owner. I have found a KB Atricle on this:
"A new follow-up activity is still owned by the original user after you change the user in Microsoft Dynamics CRM 4.0" Article ID : 948008

SYMPTOMS
Consider the following scenario in Microsoft Dynamics CRM 4.0. On an account form, you try to create a new follow-up activity in the Form Assistant. In the Form Assistant, you change the user in the Assign to field to another user. Then, you click Save and Open. In this scenario, the new follow-up activity is still owned by the original user who was in the Assign to field.

This problem also occurs if you change any field in the Form Assistant that is mapped between the source entity and the selected activity entity. For example, this problem also occurs if you change the Phone Number field in the follow-up activity. The Phone Number field is mapped to the Main Phone field on the account form. In this case, the value that exists on the source entity overwrites the value that you specify in the follow-up activity.