I always play safe - if I want to mention FTF in my log but ensure that it does not add to my FTF count I use spaces, as in "Just missed out on the F T F" or avoid the phrase entirely, as in "Just missed out on the empty log book". Either method works well and I have never had a false positive.
Apparently there are other phrases that will trip the FTF filter. However I do not know what they are.