212+ fried my mobo?

Long story short, I'm convinced my 212+ shorted a motherboard

I built a computer for a friend using an ASUS H81M-A mobo and a 212+ for "insurance" since he isn't an overclocker but could use some superior cooling. Computer didn't start. I tried everything, even RMA'd the mobo. Turns out, once I put in the stock fan/heatsink, everything worked fine.

The 212+ was installed properly, had the insulated backplate pads on there to prevent contact so what could it be? Thermal paste was properly applied without excess over the cpu. I'm not an electrician but the metal stand offs directly on the motherboard doesn't sit right with me but must be okay since it's such a popular product.

Now that it works I don't dare try to put the 212+ back in his rig. I'm just trying to understand the situation because I'm about to rebuild and I'd like to use this 212+ sitting in my computer room but am afraid I'll have the same fate or worse. I've read people having the same exact problem as me.

Use rubber spaces on the stand offs? Rubber coat the stand offs?

Any thoughts?

 
Solution
Have found it best to snug them down not overly tight, many want them and figure they have to be real tight, which actually can damage the mobo

Tradesman1

Legenda in Aeternum
You may have overtightened it, which is fairly common, have seen a few that were overtightened all the way around and wouldn't boot, more common is overtightened in a corner or side to where it keeps the CPU from sitting level and having full contact with all the pins which often throws off the DRAM (i.e. being able to run multiple channels w/ DRAM)
 
Overtightening could be it...

I have a Hyper 212+ on another build and here is something I thought was interesting. I think CM packed the wrong stand offs at one point. Look at the difference between these two. All the other parts are 100% identical. Both are Hyper 212+ about 4 years apart.

dfk0b4.jpg