Simply put, all sockets will bend the CPU as they're all being made according to Intel's specs. The socket will only clamp the CPU in the middle, while the heatsink can deliver equal pressure to the whole CPU.
You shouldn't run into this issue, as per Igor's review, if you can mount a backplate before inserting the CPU. For all regular heatsinks though, the washer mod can help to keep the CPU "flat".
It's easily reversible, so you may just try it for yourself.