Issue with SSO Certificate

I am running into the following issue within our SSO configuration after upgrading to a newer version of Ping Federate:

2021-01-15 21:30:28,323 [ajp-nio-0.0.0.0-8009-exec-4] INFO  com.appiancorp.security.auth.saml.SamlFilter - Authentication Error: Error while trying to authenticate the token: com.appiancorp.security.auth.saml.SamlAuthToken@498fd1ac: Principal: null; Credentials: [PROTECTED]; Authenticated: false; Details: AuthenticationDetails[ts=2021-01-15 21:30:28.309, entryPoint=PORTAL, clientIpAddress=216.238.132.75, clientUserAgent=Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.198

java.lang.IllegalArgumentException: Last encoded character (before the paddings if any) is a valid base 64 alphabet but not a possible value

The error appears to be something certificate related, but I'm not sure but the certificate has not actually changed on either side of the SSO setup.