My understanding from reading the WP template hierachy was that when I set my a page as my posts page in settings > reading settings that Wordpress should use archive.php. Instead it uses index.php.
Obviously I could just put my code in index.php and my site will work. But it doesn't seem like best practice, and I can't find any documentation of best (or good) practice.
Why doesn't Wordpress use archive.php in this circumstance?
And would using index.php as my posts page have unintended consequences?
Note: I've been using the _s theme as a base, but I've had the same problem with no theme base or parent.