FS#25914 - Spirit Shell and Battle Fatigue
I think the absorb from spirit shell is getting hit by battle fatigue twice somehow. Without battle fatigue the absorb from spirit shell is always bigger than what the heal would have been, because its buffed by disc mastery. With battle fatigue though, the absorb is always smaller than what you normally heal for.
https://gyazo.com/7d534e1dab3fb7b1a302c0116a385ccd 47K heal
https://gyazo.com/4125fdb20c444afcf2ad91f8ab26d6fe 31k absorb
imagine using a 1 minute cd and getting weaker by it