Yes, the default signature maximum file size was reduced in new versions of Java platform. At the moment we’re looking for a fix. The proposed workaround that you’ve linked should work, use the following value -Djdk.jar.maxSignatureFileSize=28000000.
This issue was fixed in GroupDocs.Viewer for Java 24.4. This version does not require setting -Djdk.jar.maxSignatureFileSize=28000000. Please let us know if you have any questions.