I think there’s a bug with how this site, and also Ideone.com, are executing Haskell programs. It’s affecting the judging for CHEFHPAL.
Whenever a Haskell program produces more than approximately 64K of output, the testing environment crashes, with a NZEC. I am able to get it to run by artificially adding a limiter, but since the correct answers are longer than I am allowed to print, the program is then marked WA.
Here is a MCVE that reproduces this bug, and gives no hints about any problems:
main :: IO () main = putStrLn $ unwords $ map show $ [1..20000]