Cold Snap on Frostbolt doesn't seem to do Cold Snap damage and remove freeze

Description in Cold Snap says casting on Frostbolt should explode the Frostbolt, causing Frostbolt explosion damage. If it also hits a Frozen enemy, Cold Snap damage is also applied and Frozen status is removed.

The bolded part doesn't seem to be working. This is a huge problem on controller, as Frostbolts are prioritized over single frozen enemies, causing a lot of wasted mana.