How to compute panel bus bar stab and breaker spring clip electrical contacts area
All Siemens load center bus systems are exactly the same and have been for decades, going back to when they were ITE brand before Siemens bought them in the 1980s. Nothing has changed. If this were a design issue, there would be countless fires, lawsuits etc. Siemens is the world's largets electrical company, something that lawyers drool over. So they would be all over this like stink on a pile of poo.

So there are three possibilities here;

1) You have a COUNTERFEIT breaker, which has been happening a lot with breakers being sold over the internet, even through big outlets like Amazon.

2) You bought a used  / "refurbished" (no such thing) breaker and it had been subjected to a lot of heat, likely due to overloading, to where the springs have lost their tension.

3) You have a defective breaker. It happens, but generally Siemens catches it and issues a recall. Now, as it so happens, there WAS a recall of this series of breakers by Siemens back in 2010 for this EXACT reason! So whomever you bought this from either failed to notice that, or pulled them out of a garbage can back in 2010 and is selling them at 100% profit. If you can prove that you bought this from an AUTHORIZED dealer of Siemens equipment, they will likely replace it for you. If you bought it from FleaBay or Amazon or some surplus site, good luck with that... When the price looks too good to be true, it is.

https://www.cpsc.gov/Recalls/1998/cpsc-siemens-energy-automation-inc-announce-recall-of-gfci-circuit-breakers-used-with