Hello I just wanted to notify you that I have what seems to be the exact same problem as FrankQ. After recently updating my macOS to Monterey 12.6 I started to get this error when trying to sign data. Previously it was not a problem whatsoever. It works the first time when I restart my mac but after that it stops working completely. I have updated to the latest dotnet SDK and runtime versions as recommended by some but without any success. The code runs in a dotnet console application. The error message looks just like FrankQs so it's redundant to post it.

Thank you for the reply and yes that's sounds like a good idea. However, I have at least found a temporary solution for my setup and I will share it in case it might provide some value for future forum visitors. So I updated to the lastest dotnet SDK and i use Rider as my IDE. What I realized is that I could get around the error if I did a clean build of the solution every time I altered the code in the slightest way. It's a bit tedious but at least it got me back to be able to work. That's all thanks.