The first was not serious as it did not affect game play at all and turns out to be a RB engine issue that can be seen in a Disc song.
The second one was a true charting mistake, albeit one from piano charting that is less likely to be caught (but should be) because it is a lesser known and used concept.
I agree that if any errors, no matter how big or small, make it through then they need to be pointed out. Having a running thread of these on the creators site would be useful for what to keep an eye out for. People mentioning them on this forum in a calm and educated manner would also be helpful. People making end of world statements because they believe something small might be a mistake, not so much.
RBN is a large and still really new concept. There will be issues as it moves along. The main thing is that we learn from them and continue to make the process better.