did chromium become another type of fluorine while we all weren't looking or is this just a fun fact wholly unrelated to the bit about PFAS upthread?

The concern is twofold. First, chromium is an element and as such does not break down, it can only be secreted. Second, the higher oxidation state Cr(VI) is a known carcinogen. It's claimed the Cr(III) here will not oxidize to Cr(VI) under normal cooking conditions, however.

My understanding is the claim that Cr is a necessary micronutrient is disputed.

so... wholly unrelated to the claim that it's impossible to make parchment paper without polyfluoroalkyl substances which is what was being refuted in the thing you replied to?

I was pointing out a concern with that non-PFAs solution.

I also understand the silicone in current parchment paper isn't a PFAS, as it contains no fluorine.