Possible rust on Auto orange sherbet?

Not the mulch. Use this mulch on all other plants in yard, 48 of them. Have used same mulch for ten years at least. Naturally alkaline soil negates effect of minor amount of cedar chips. Dye is food grade, no chemicals. It was a nutrient deficiency, potassium to be exact. Soil test confirmation. Thank you so much for the feedback 💜

I would say it has something to do with the wood chips, they can be highly acidic and contain a lot of tannins which could cause all sorts of lockout issues. Straw is a far superior mulch.

Actually I use a LOT of calcium...bonemeal and old eggs get composted, plus I admittedly use Cal mag even with the excess mag. It's never caused a huge issue..I was actually thinking an EXCESS of Calcium....but then again, it's JUST this one plant and it's the only one if this strain. Other veg and plants 2' away are perfectly fine ... I AM leaning towards a calcium problem though ...? I flushed it pretty good today, see if it helps. Thank you!

Rust color is usually calcium deficiency - which makes sense here because if you're saying your soil is naturally higher in magnesium, then you're missing the other half of cal/mag, and I'm betting you probably haven't been using very much (if any) cal/mag when you feed.