We now have a custom “How to Answer” pop-up (yay!). However, this pop-up isn't shown to users who come here with the association bonus from other SE sites. In general, this behaviour makes sense: the pop-up is the same virtually everywhere and it teaches people how the Q&A platform in general works, not how answers on that specific site should be written. However, as the custom pop-up shows, answering works a bit differently on PPCG, and we also get a lot of wrong/invalid answers from active SE users who are not familiar with the difference of PPCG from the rest of SE.
Hence, it would probably be helpful if this was shown to all new users, regardless of whether they come here from another SE with an association bonus or whether they arrive here directly. Since changing the text on a per-site basis was doable on SE's end, maybe changing the conditions for when it's being displayed might also be an option?