I was the first developer to take a look at this vulnerability, and we immediately recognized the flaw  described in the mathematics.
What you're saying is simply untrue, https://github.com/shadowproject/shadow/issues/25#issuecomment-182977494

A flaw in theory doesn't immediately mean that it's applicable to the software in question.
I did not code our ring signature implementation so it took some time to find all the details about the OpenSSL libraries we use.