I have a signifcant problem in many of my assemblies with concentric mates breaking. What happens is that for some reason, it cannot find one face of a part when two have been mated concentrically. This happens so frequently and in large assemblies and I'm getting really tired of wasting my time having to reestablish them. Not all concentric mates break, only some. Assemblies can be fully resolved or not, rebuilt or not, lightweight or not - it doesn't matter.

It's been happening since using 2009 and I'm now on 2011 SP3.

Anyone else have this problem, know what is going on, or how to fix it?