So I had the most bizarre experience after 40 plus years this last 4 days. I have been using Apidra for years with the steel set. I have been using Tandem and steel sets for 6 months, no issues. I opened a new box of sets and also a new bottle of insulin last week. I was having clogs within 12 hours and high blood sugar from the beginning. I assumed I had a bad lot of steel sets, it was clear the amount of insulin that should be getting delivered was not. It all came out of the Tandem cartridge just fine, the issue was the pig tail section. Even without a clog alarm I could see that less insulin was coming out of the end point than any of the other points, but this was always after at least 6 hours. So I assumed the connector did not work right or the needle part was a bit too small or a bit dull so I got more tissue in it when I placed it in. However, I went ahead and switched out my insulin to a new bottle and voila, all issues disappeared!!! So I am thinking the insulin froze and the molecular structure changed which made it clog up the steel set. It did not impact the tubing or the cartridge but maybe impacted the steel? So bizarre. Any brilliant ideas would love to hear.