Elemental shaman and Symbiosis

I'm joining 2s with a rdruid and as an elemental shaman i should be able to use the spell Solar Beam as the result of Symbiosis, which silences everyone who stands in the area of effect of the spell. I noticed in one of my last arenas that the enemy resto shammy, though rooted and beamed (through Symbiosis), casted at least Riptide and Hex.. So i'm asking other ele shammies if you also noticed this bug or if it was just a single, unfortunate case.

Symbiosis Solar Beam doesn't work as intended I think someone already posted it on the bugtracker, all we can do is hope they fix it