I don't normally bother charging frost no. I'll have to start trying though if thats the case. I usually drop a timeshift on my enemy too so maybe thats being screwing with it a bit. I'm quite certain that uncharged frost doesn't apply any snare as I've been running from enemies and using it(& no other spell) and its done nothing but damage. Would also add that I've found that in PvE the CC from frost doesn't always trigger on mobs even when it's the only spell used.

I'll post back here if I find anything useful regarding charged frost in PvP.