I have an issue with selectors where the UI presentation does not change when using rbf_setfieldvalue to change or clear the value of a selector. It seems that the value is being changed, but only on the hidden input field. Since this isn't presented to the user the selector still "shows" the previous value.
I believe that this may be the same issue that is referenced in the following treads:
Is there anyway to clear a selector client-side including the UI presentation? As mentioned in one of the above treads setting to null will change the value of the hidden input, but the selector still presents the old value.