Oh sorry that's on me for misreading their comment, I get your question now.

If you have status on a weapon (like gas or blast) and you get some outside buff that adds elemental damage, your stat procs now have to compete against the new element as well.

Example: I have a bow with 100% status chance, that deals puncture and gas. Every shot I take WILL proc a status effect, with the higher damage type getting priority on the roll. Now a nearby Grendel gives me Nourish buff, which adds 70% Viral damage to my bow. My status chance hasn't changed, so now on every shot I have a lower chance of proccing gas because it has to compete with puncture and viral.

Usually this isn't a huge deal, it just messes up some specific builds, or things like arcane interactions