Apparently you cannot use the tailoring nets while in metamorphosis because it gets rid of meta and you just wasted a 3 min cd.
Mounting getting rid of meta is understandable, but using nets? For fucks sake, what is next?!
With all the mistakes they have made with metamorphosis they might as well rename it:
Bug-o-morphosis
3 min cd
Transforms the warlock into something that won't really make a difference and increases your chance to get a bug/be bugged by 100%.
Someone should report this bug in the blizz bug forums btw.