are you assuming the other element is also in the filter? my assumption is your 'deletions' occur only when you know before hand the element already is in the f

are you assuming the other element is also in the filter? my assumption is your 'deletions' occur only when you know before hand the element already is in the filter. if two elements with the same fingerprints are added to the filter, the finger print is stored two separate times. deletion of any one of them would effectively remove only the single copy thereby not affecting the other (you could be deleting the fingerprint that technically belongs to the other element but it's all the same), so no in this case you do not get false negatives.