AMD AM2 socket heatsink causing motherboard to bend

I've got a problem with two systems that I have here. Both are running a Gigabyte GA/M52S-S3P motherboard with an AMD Athlon 64x2 CPU's, one being 4600+ and the other 6000+.

I've had the same problem with both of these and it's scaring me badly. When I install the CPU into the motherboard it's fine, but when I go to clip on the heatsink for the CPU, I can't put enough pressure on the cam lever to get it to sit down as far as it's supposed to. I know these things have to be a tight fit, but any more pressure on that and I'd have snapped it off.

What I've found is that because of this, the CPU is being pushed down WAY to far on the motherboard causing it to bow. Because if this, the whole thing stops working. Things power up, but the systems don't even get to the BOIS screen.

If I take the pressure off and leave the heatsink sitting there just clipped on but without being forced down, it works. This still gives me a relatively decent amount of pressure on the CPU as far as I can tell, but I'm still worried that this will cause issues later on.

I've tried both of the stock heatsinks as well as a Thermaltake aftermarket one, and it's the same deal for them all. Is this a common thing, or does it sound like there's some major problems with this??