Yes, that’s normal for L1 and L2, WordPress creates ridiculous queries like attachment, categories, etc. but never 404
404 detection runs later, but on your web there is 404 generated very early, so there is something else modifying query.
I understand that you can not give me access, but you should setup some demo website where you can replicate this problem and where I can work on it, because I’m not able to replicate this.
I have no idea what plugins you use and what settings you use and as this is a free plugin, I’m not going to spent hours by trying to create some demo website, that will have same error – you have to do it and then I can help you for free
Maybe you can use wpsandbox or something else
Or if you’re skilled programmer you can figure out what plugin is in conflict and then let me know and I will fix it, but I have no information to work with now.