Yes, The Secret War of Harry Frigg (1968) was not funny and a turkey all around. Paul did do ok in The Rack (1956), Until They Sail (1957), Exodus (1960), Torn Curtain (1966) and Fat Man and Little Boy (1989) (5 more I missed!), but he Frigged Up in 1967...
I'll agree it was a turkey, but Paul Newman has such gorgeous blue eyes...and I was a teenager at the time. (!)