the tera flex ones are sketchy..they unload when u jump speed bumps and lift up when u hit corners hard.kinda sketch..but going that fast is sketch too..so i guess it goes hand in hand

I believe the Tera-Flex would do that. They have a rotational piece in them that lets them flex out much easier, so, they droop out easier. I can't comment on the jumping 

I've had my double shackles on my DD for 2 years and NEVER had any unloading/separating/problems with them. I have wheeled the snot out of them. The only problem I ever had with mine was when i was on my side in a canyon in Hollister and I tried to highlift myself level. The driver rear tire was rubbing on the side of the canyon wall and it was holding my tire down. I maxed out my 60" highlift and my tire never left where it was. Failed! Like I said, only problem I have ever had