AStacy2, what's happening there is that Reaper, during quantization, will sometimes extend (both ways) the item from it's Snap Conform marker. That means that if you have a kick hit that has a snare right before it and the quantization messes up, the kick may be quantized but it's region could have been extended before it making a random, misplaced snare hit. I have that problem a lot, but i've found that if you take a few extra minutes to make some preliminary grid-alignments, those mistakes are generally left behind. To any and all, I'm currently working on streamlining this process. Once I get it down, I'm gonna make a video using some faster, metal-based music to prove it works well. Cheers!