Can someone explain how searching for Eevee* ~autofellatio ~autocunnilingus returns the post #5169162 Since from my understanding it’s searching for any posts that contain the tag that is/starts with Eevee, and from those posts; posts that either contain autofellatio or autocunnilingus or both.

So how is it showing me a post that doesn’t contain a tag that starts with (or is) Eevee

hmm... seems like it's treating all *'d terms as ~.

I think that this is a new issue. although, I'm not 100% certain this hasn't always been the behaviour, I'm not sure how often I've used both at once or multiple wildcarded terms.

(in the meantime _{or whatever} the search eevee* oral_masturbation should be what you're looking for)

This isn't a new issue and really isn't fixable, as the cheatsheet says wildcards do not play well with other syntaxes, ~ especially
Each of these use the same should
https://github.com/e621ng/e621ng/blob/10b9389c23a14195a4d1dec64595382ff7ffb215/app/logical/tag_query.rb#L363-L367

it's practically just expanding out eevee* into ~ of all of the matching tags