It appears that there is some sort of spawning behavior near the darkened "Google" tiles. I paused, turned off all the cells in the region (taking into account wrapping from the other side) and let it go. Cells started activating near the 'e'.
I can confirm this. I wiped all tiles and stepped ahead a hundred frames, but nothing new appeared. As soon as I hit 'play' though, within a dozen or so frames a few random tiles appeared in the vicinity and the area was soon teeming with life again.