Figuring out what is going wrong in my React Game of Life

Hey, so I’m working on my React Game of Life project, and I seem to be facing a problem with either my rendering of each incremental generation or my initial rules. My CodePen seems to allow exponential growth, one of the things that definitely should not be possible in Conway’s Game of Life. Patterns such as still life still seem to work, and I have checked in a 10x10 grid that the correct tiles are being checked when my app checks the 8 directions around a tile. This leads me to believe it has something to do with the check I currently have in place to determine the number of living neighbors, the actual rendering or updating itself, or some other thing I haven’t been able to figure out, yet. You can see in lines 64 - 108 the function that I am using to check the neighbors. Any help in figuring out the issue would be greatly appreciated.