I used a Computed for display field to keep a list of fields that I wanted to test against emptiness.
Using the procedure both on the Web and in Notes, I had the unpleasant surprise to notice that in the Notes client, I lose the ComputedForDisplay info after uidoc.refresh.
Is that a bug?
I know of no bug that would make CFD fields vanish during a refresh. However, the value of the field is recalculated when you refresh, using the field formula. That's not a bug; that's how it's designed to work.
If you mean that you have code that changes the value of the field, and you need to keep the value when you refresh, then you must write the formula to incorporate the existing field value. For instance, the formula
@ThisValue should let you refresh without losing any information.