We have a winforms app built on .net 4.7. I have included an instance of SingleInstanceController : WindowsFormsApplicationBase to prevent multiple instances from running. We have 1200 installations of our product running on various releases (from v 2.5 to 2.12) on various versions of Windows.
But for a handful of customers - like 10 out of 1200 - we see duplicate activity: Our system processes a document on the PC and sends results to our API, and we are detecting duplicate transactions. We send log info to AWS and even there I see duplicate log messages, down to the 100th of a second: (see attached image)
You can even see the SingleInstanceController logging twice.
It only happens to a few customers, and even for them, it is not every time they run the application. We have been unable to recreate the problem on any dev or test machines. Any ideas on what could be causing this?