I have a pair of Kastle K12 CTI bindings on my BMX 128s. When the boot is in the binding the heel piece that holds the boot heel has some up and down springy play in it. I'd say the heel can come up maybe a few mms. Both bindings are this way, and even without the boot in the binding, if I push the heel piece down into the position as if you are clicked in, I can wiggle the heel piece up and down a bit. I have checked forward pressure, and it is set correctly. It seems like the binding is designed this way, as if it's a kind of progressive release, but I've never seen any other binding that allows the heel of the boot to come up off the binding plate like this, especially without much of a pull upward.
I know there was a recall of these in the 2010-11 year, but I bought these last year (I suppose dealer could have sold me previous model year bindings, but don't even know if the recall was about an issue like this).
Hoping someone out there can conform whether it's the way the binding is designed to perform or if I should be getting them replaced.