Classloading issue - java.security.cert.CertificateException: X.509 not found

Issue

We deployed an application in 3 distinct servers. The same WAR package was deployed in approval, pre-production and production environments, as usual. In the first two environments, the signature feature works normally. In production, attempting to sign the documents (one of the most important features of the system), we received the error below:

Caused by: java.security.cert.CertificateException: X.509 not found

The class specified in the error (org.bouncycastle.jce.provider.JDKX509CertificateFactory) is inside of WEB-INF/lib directory. The library is  bcprov-jdk16-145.jar. It works together with the library bcmail-jdk16-145.jar. Apparently the library is not loading, or some of its dependencies can be loaded from another point that can't find that class.