Could it be that you enabled sv_cullentities on eR33t servers ? We played on eR33t Match server today and it was rly freaky. Our pings were higher than normal (around 250) and sometimes gunmodels or playermodels dissapeared for a second.
This is accurate. Unfortunately, since this is the "best we have" from a cheat detection/prevention stance, and development is unwilling to allow any hooks or outside cheat-detection development, those with high ping times may experience less than ideal play conditions. In a perfect world, we'd have some form of psuedo-opensource anti-cheat options where we could actually really fix the issue without obvious flaws in the current systems. Until then, on our servers, HPBs will have to deal with some of the 'bugs' associated with the current implementation.
Again, this kind of thing has been dealt with effectively in a myriad of other FPS games, for many years, in games with exponentially larger communities. It's unfortunate that we are so far behind.