Field is on the view but isn't visible

Hello,

I have a field, that isn't visible on a view. However, if I try to add it with the button "Add Columns" it isn't in the list.

If I try to configure sorting I can choose the column. The field is in the list behind the last visible value. 

Moreover, in the list of find columns it also shows up. 

However, I cannot see the Column on the view. Not in the solution and not in the system.

I have this problem in every view of this entity, but only with this one field.

This field isn't included in a business rule or a workflow. It is only in a Business Process Flow as a required field and on the form it is also visible. Only the Column in the views isn't there. 

Has someone an idea how I can make the column visible?

Thanks in advance

Amber