Weird CB2.3 problem (heel slippage)

[ice04]

I have 2 pairs of 2.3s. One is the white/gray (US8) general release, the other is white/blue (US8.5) rafa clay season. I can't explain why the white/blue ones (the larger ones) fit me better, even if its larger. And the issue is, the white/gray has heel slippage but the white/blue has none. Can someone explain what's the reason for this? Thanks for any answer.

 

[UnLeaDED_GaSoLiNE™]

I have an issue also with my courtballistec 1.3 in my normal size 9 vs no heel slippage on my 2.3s in a size 9.5... You are right it is weird, I don't know why this is the case but I have found a solution from reading the forums, using a technique called lock lacing. It doesn't eliminate heel slippage 100% but it is a whole lot better.