What behaviour did you expect? The default without any rule is "FALSE". There adding just one rule with "=> FALSE" won't change anything. If you add an explicit default rule "TRUE => TRUE" then everything else except those rows matching the first rule goes to "TRUE". This is how it's supposed to work.
Well, that is what I did, two lines (sorry if my writing above was unclear):
LINE 1: bla-bla => FALSE
LINE 2: TRUE => TRUE
but only one output has any data (in this case the true, but nothing in false), it's not like the false ends up in false and the true in true.
(and yes, there are sufficient cases for both false and true in my data set, can be "verified" by removing LINE 2).
Or maybe the misunderstanding lies here: will there only be one output? For my usage to be useful, both outputs have to be generated (well, unless I do a logic operation of output with input table, alt, two times this node in parallel with opposit statements).