No, spell check would have caught every sentence with a missing period (and there are QUITE a few of those). So... they didn't even use that! I know what you mean, though, Gabriel.
This is why I hate, hate, hate the fact that we're approaching entering an era where no one is required to be a master of English language composition -- even if their job demands it. Editors are the last line of defense between a perfect book and one riddled with errors.
This little editing situation truly hurts Shadowrun. As Gabriel mentioned, it doesn't take an insane English wiz (like yours truly) to notice these errors; some folks will begin to think it's a subpar system -- consciously or unconsciously -- based primarily upon the shoddy editing work. When the editing is perfect (as in Blue Planet v2), the game truly stands out as excellent; it lifts the game up. When the editing is bad, it brings the game down, makes it seem less... intelligent.
I wonder if FanPro needs a new editor? Bah, they won't hire me... I don't actually have a degree yet, and demonstrating one's editorial skills off the cuff is always difficult. Whomever their current editor is, I'm sure he's complacent and has a bit of tenure around his workplace, and God forbid you replace someone these days on account of mere incompetence and job ignorance.