I looked through the skills and I think i don't quite understand your problem. Correct me if I am wrong, I might have misunderstood your problem.
"Ice Summoning" only grants buffs, it would not trigger the Trait: "Freezing Aura" since it does no inflict frozen to the player. But even if it did, it would cast no all hitting skill anyway.
Only "Frozen Self" and "Ice Howl" can trigger the aoe bonus skill if the conditions are met. If you got the upgraded skill version of "Ice Summoning" it does grant the Aftershock Buff, which is a aoe extra hit if you are refering to that but that would have nothing to do with "Frozen Self".
But i did found a problem with "Frozen Self" not triggering correctly and fixed that. Maybe that could have been related to your problem
The one hit you're getting is most likley from the "Ice Shard" Effect which you do get through "Ice Summoning":
