All I can say is that, from new, the connection on my Cyrus 8 amp is the loosest that I've experienced. I've tried different plugs.
I can feel that those 2 pins are not going deeply enough into the receptacles. If I had to guess, I'd say they're going no further than 5mm in. (Therefore hardly clearing the splayed openings of the receptacles).
Also, more than is usually the case with IEC connectors, the pins and their receptacles seem to be doing all the holding - there's not the normal feel that the plastic bodies are taking any strain.
(And why bother with 3 pins when only 2 are required right?)
As has been said, don't worry too much as long as you've got a connection.
In my case the back of my amp is not exposed, so I just make sure the connector is fully in, then it's never touched. I'm not overly bothered but it's very loose and one day I may fit another chassis connector on the amp, as I feel sure that would cure it - and of course it won't hurt that it will have 3 pins, even if manufacturers have decided that an unused earth pin serves no useful purpose!