Posts missing from your listing template on first page load (before using any facets) can be caused by several reasons.

First, make sure you are not unintentionally filtering the query (for example by category or a custom field). The way you could be doing that depends on the type of listing template you are using. For example, when using a custom WP_Query, you could be setting a meta_query argument, or you could be using a pre_get_posts hook. When you are using the Listing Builder, you could be using query filtering rules, or the facetwp_query_args hook.

Next, check if you are ordering the query by one or more custom fields that do not exist for certain posts. If this is the case, you need to either make sure the field exists for all posts (usually by saving them), or adapt the meta_query to account for both the existing and the non-existing custom field(s).

See also