So we have a really decent sized what I'd term as a stock pot made of what I think is stainless steel. We have used it a bit over the past few years.

I went to make a pot of Chilli the other day, put it onto our gas stovetop and heated it, with some oil in the bottom.

It started making a really odd creaking popping noise I've never heard before. I am not really sure how to accurately describe it.

As we started to heat the ingredients, we found that 1 second of the lower side at the back was getting really dark and food was starting to stick and slightly burn there.

I can't see any structural issues, but the discolouration has stayed even after giving it a good clean.

I am wondering if something has happened to it?

Anyone seen this before? I can post a photo if required.