In Pre-intermediate/JLPT N4 Grammar lesson #23 "Cause and Effect" (ので), about halfway through, the explanation reads "It cannot be subjective: a believe, feeling, or opinion..." which of course should be "belief".
It's not interfering at all with understanding, but I'm a recovering copyeditor so I can't help noticing things like this.
These kinds of errors usually get fixed, as long as your report gets noticed. I reported an "a/an" mistake a while back, and it got fixed relatively quickly.
