I was not able to precisely reproduce the issue, but I could get a situation in which the same certificate has been created twice in a row (the second overwriting the first one). By analyzing it, I found a timing issue which, in fact, can also explain your situation.
Please download the recent version, install it, rebuild your project with new assemblies, and re-test. It is available on NuGet and on our Web page. The version with the fix reports itself as 5.54.1281.1 or later.
we would like to use static method EasyUAClient.Install for certificate generation. We noticed, that one EasyUAClient.Install call generates two different certificate files in certificate store ("%CommonApplicationData%\OPC Foundation\CertificateStores\UA Applications"). Is there any reason why two files are created ?
Thank you for your help.