These are the only RCA's I have ever had problems with in my lifetime. 3 pair broke on me because there is a lack of a decent strain relief.
The "Hexagon" connector was very snug fitting and very hard to get a good grasp of because it was perfectly smooth and straight. This led me to pull on the cable itself many times. With good cables, the cable itself should be coupled with the interconnect itself IMO.
There were no flaws in the actual wire itself - and they look very nice also, but WAY overpriced. I purchased mine for less than your asking price in 2001 when they were new.
If you look at Stingers top of the line right now.. the HP3... you will see they addressed these issues with a contoured connector and rubber grips which specifically are stated in the specs are used to help twist on/off the connector.
I hate to be a horrible post dumper, but you seem to be posting like you have something special on your hands. Either keep them or toss them in the trash like I did.