I'm assuming once per short rest is intentional though I guess you could try reporting it as a bug to Larian to see if you can get confirmation.
I'd disagree it makes it useless, at least for me given I don't tend to use it multiple times a day anyway. Out of interest, how do you use it such that once per short rest isn't useful?
Because it's a cantrip. The whole point of cantrips is that they can be used at will because they're not strong in the first place.
