Something that annoys me is stealth errata. Not changes to the rules of stealth but changes between printings of the PHB that are not described in the errata PDF.

Let's look at the Help action again. The text is divided in two paragraphs. The first paragraph talks about giving advantage on an ability check, then there is the "alternatively" paragraph about giving advantage on an attack roll. The rule that you need to be able to do the task yourself appears in another part of the book, which is about ability checks.

I am away from it at the moment, but I am pretty sure that, in my copy of the PHB, the first paragraph of the Help action tells you to read that other part of the book. So when the "alternatively" paragraph comes, it is (a tiny bit) clearer that it is its own separate thing. But that's not in the 1st-printing PHB, and the errata PDF makes no mention of the change.