Why does the gre0 interface have frame errors on Red Hat Enterprise Linux 6.5, but not in earlier versions?

Issue

• We recently patched several RHEL 6.4 machines. The Squid package was not updated, and the config files were not changed for our GRE interface or for Squid. The patched machines are no longer accepting traffic through the GRE interface as they did prior to patching. I will attach two separate files to illustrate differences between these servers.

• When upgrading to RHEL 6.5, a gre0 interface made for a GRE tunnel from other networking hardware, may start dropping frames.