That separation is a common issue with both 30 and 50 amp plugs. I did the "goop" and tape repair that ACE has suggested, that worked for several seasons. After that repair failed I replaced the plug as the Judge suggested.
I think I already know the right answer but have to ask...
The male plug is separating from the wire. It appears to be solidly connected, other than the coating.
Should I goop the heck out of it or replace the male end?
Common problem. The cover creeps back each time you roll up the cord. Just start back about 20 feet and slide cover back to plug and reset it in plug end. Super glue it with JB weld or similar product.
My plug is now 7 years old and holding tight and still waterproof. No tape or new ends.
Both RVs Iíve owned same problem same fix. Never a problem again.