For some reason setting the
post_type query variable to
page doesn’t have the desired effect. Other post types (
post, custom post types) work, but
page doesn’t do anything.
This is not a Relevanssi bug, but a WordPress feature (see this trac ticket). If the user inputs a bad value to the
post_type query variable, WordPress changes it to
any. For some reason that happens also when the
post_type is set to
page, even though that should be a valid value.
There’s nothing Relevanssi can do about this. However, there’s a fix. Relevanssi introduces a new query variable
post_types, which happily accepts
page. Use that, if you need to filter by post type.
(Update 19.1.2021: This WordPress bug still isn’t fixed!)