Soapenv namespace is not added implicitly or explicitly on Redhat

Tested with Linux  (Red Hat Enterprise Linux Server release 5.11 (Tikanga) and 7.5 (Maipo)), namespace for soapenv is not being added, tried to add it implicitly, doesn't work.

The only workaround I was able to do to fix this is to use SOAP 11 envelope, and add it's namespace, so seems like this error is specific to SOAP 12.

Java version in Linux: jdk1.8.0_92

Java version in Windows: jdk1.8.0.161

p.s in windows everything works fine, I don't have to specify envelope's version, or namespace URI.

another p.s: this issue had been there since version 1.6.2, and I believe it's OS specific, should try it on newer redhat OS.

Update: I've tried it with Redhat 7.5 Maipo, same issue