Thanks for your discovery of typographical errors in a recent column.
B/R has a staff of both content (what is said) and copy (spelling, grammar, typos) editors that review stories by B/R's writers. Unfortunately, some things still get missed, even with more than one pair of eyes looking at an article.
It's extremely difficult for writers to see their own typographical mistakes, and it can be almost as difficult at times for editors to catch them in certain circumstances. It seems, however, that you have a keen eye for these things. Perhaps you might consider applying for a copy editor position with B/R?
You can always submit errors you notice to firstname.lastname@example.org as well.