Today we had a C5 we thought was failing. When the technician got to the site, he found the RJ45 boot/cover was full of snow. I had him load the connector up with the included grease and the issue appears to be gone.
My techs had complained about the quality of the RJ-45 cover on the C5, but they’re used to the screw on type with rubber gaskets. These appear to work as more of a protective cover with the grease intended to keep the connection dry.