Loose Icicle Question

So I have been "grinding" the mob loose icicle and have only been getting a single emerald each time is it supposed to drop anything else and if so how likely is it to drop since its the only place i can guess that i can acquire a frosted chunk

 

Unfortunately, this is a bug. Like you said, it is supposed to drop the frost chunk, but it just drops 1 emerald instead. Iirc, the mask itself is tradeable, but there's going to be practically no one selling it.