I have the stumble.
I just let it warm up or give it a bit more gas/feather the clutch for a split second when I take off cold.
Until someone mentions it,I do not notice it.
As far as it being a filter or screen issue,I don't think it has anything to do with that.
Here is why.
There appears to be more Goldwings/F6Bs with the stumble than don't have it.
Every one of them has different miles on them.
I don't believe all of these bikes can have a filter/screen issue.
On a side note...the stumble as it is called has never caused a concern for me.
I just ride.