Sacred Wisps + Barrage "when you fire a projectile"

Bug Report ID: #2696927838

After a few minutes of testing, it would appear that Sacred Wisps support, despite the unique wording of "when you fire a projectile," instead rolls once per skill use.

Tested with Barrage + LMP (7 projectiles) and 2 wisps, which should be 14 rolls, but success rate looks much closer to 2 rolls. (didn't collect exact data but the difference between 2% failure rate and 56% failure rate is fairly obvious on about a hundred trials) When testing, I made sure wisps were summoned and not in the middle of an attack animation.

Apparently this wasn't always the case, but no change appears in any patch notes. For that reason and the wording, I believe this to be a bug.

Should be a wording slip-up, I think it's been always working like that.

GGG even constrained the chance to use the triggering attack in presence of a rare/unique enemy to 50% (from 100%) for the performance's sake (pre-launch)
https://www.reddit.com/r/pathofexile/comments/1bnut66/comment/kwkqttg/ which means they are not in favour of frequent procs.