Is it really a problem? Kitting was also a thing in Baldurs gate 2. If Player want to cheese guerilla the game, why not?
The description literally reads that it shouldn't affect enemies on full HP but it does.
Rangers will still be able to do this at level 5+ with Longbows, but they aren't meant to be able to apply full colossal hunter damage on full HP enemies at levels 1-4, or at 5+ with crossbows without a feat for multiple crossbow hits.
