I got cheated , I feel mad because my own work project this will further delay, but at the same time I feel happy, because now I have the opportunity to demonstrate in public close-up pictures of worst quality parts.
Long story sort, these are worst quality banana plug adapter.
Material this is plastic ( cheap plastic as the one used for toys that they do crack on die on impact.
BNC pin this is not properly machined, there is no sharp tip on the pin.
BNC plug (negative side this gets all the way at female BNC (instrument terminal) this is terribly machined, poor bad made shape.
Both details these are critical, and they can destroy female BNC plugs.
Real quality banana plug adapter, this has molded (rubberize surface) as external plastic cover.
High voltage similar parts from Pomona brand they have different material ( it could be Bakelite).
Additionally I decided to use HIOKI resistance meter, as another way of spotting build quality differences.
Now my last word about this topic, this is that major problem with those (FAKE) banana plug adapter this is quality of mechanical construction.
Anything that can cause damage of BNC plugs over an Oscilloscopes and similar high price equipment, this is and must be considered as garbage BNC accessory.
Replacing BNC plugs over equipment due mechanical damage, this is a costly and time consuming adventure, therefore be careful of your choices.
In my case I got cheated, but I am ready to defend my upcoming eBay case.