> i'm no English expert, but I can't take seriously an article with grammar errors :/
It's arguably a regional/dialect distinction. Here "layoffs" is being treated as a collective noun, similar to how people say "the data is" instead of "the data are". Notice how people usually say "layoffs" when referring to the entire round.
English has less dialectal variation than most languages, so English speakers (particularly educated British or American speakers) aren't used to seeing it, but collectivization of nouns is one of the more common ones to spot. If you pay attention, you'll start seeing other examples here and there.