Why is my heatstick suddenly scorching wort/mash?

I made a heatstick and it had been working perfectly. 120v 1500W element. Used it to speed up my HLT and kettle temps, maintain a boil with minimal propane heat, and even heated up a mash.

Then I brewed a rye beer, stuck it in the boil, and it scorched and ruined the batch.

I then brewed a wheat. My mash temp was low so stuck the heatstick in and I saw immediately that scorching was occurring so pulled it out before things got ruined.

Is there something about wheat & rye that scorch more easily, or is something going on with my heatstick? Not sure how many more batches I want to experiment on.

Thanks,
Jim

Higher levels of proteins in both wheat and Rye malts are the culprit, 10 minute protein rest at 125 works wonders for these beers.