It's a long shot, but my Tiger had an 'unfindable, unfixable' cabover leak wetting the edge of the mattress. Turned out to be one of the Hehr-brand side sliding windows. The lower plastic channel that the sliding window panel moves in had shifted forward in the frame. It only moved 1/4", but that was enough to block the drain path to the weep hole when parked just a little nose down. I found it by getting into the cabover bunk with a really bright little flashlight during a heavy rainstorm and spending some 'quality time'...
Jim, "Some people lack the ability to laugh at themselves. That's where I come in."