FunExperiments 157 % timbuk --fung 30 filterEvenBug.txt 

term height= 1

term height= 2

term height= 3

term height= 4
Rejected: 5
term height= 5
Completion time: 0.098521 seconds


Found a counterexample:
-----------------------
Term app(app(exists,odd),app(app(filter,odd),cons(s(zero),cons(zero,nil)))) rewrites to a forbidden pattern