Avenger Mastery barely works with Onslaught Gloves of the Sniper

An apparent sanity check to prevent Avenger Mastery from recognising more than one critical hit from area-of-effect attacks causes Avenger Mastery to interact badly with attacks which connect multiple times regardless of context - such as Bullet Ballet, Typhoon, Ego Blade Breach, Rimefire Burst, or most conspicuously, anything which triggers Onslaught Gloves of the Sniper.

The lattermost case is where the Mastery becomes difficult to use at all, leaving me at the mercy of the universe whether back-to-back-to-back criticals from AoE or single-target powers yield a single proc.