Hi – great question!
When WordPress queries run, if The Events Calendar detects that the query relates to events it does apply a little magic of its own – and, in the absence of other criteria it will indeed assume that only upcoming (future) events should be returned.
It’s definitely possible to prevent this, though, but what I can’t answer off the top of my head is how you might do this selectively so as only to impact on this particular scenario with ACF. The basic approach though would be something like this:
add_action( 'init', 'strike_down_tribe_query_filters', 20 );
function strike_down_tribe_query_filters() {
remove_action( 'parse_query', array( 'TribeEventsQuery', 'parse_query' ), 50 );
remove_action( 'pre_get_posts', array( 'TribeEventsQuery', 'pre_get_posts' ), 50 );
}
Of course you’d need to adjust and add some criteria so as only to do this in select situations.
Does that help at all?