Embedded Timeline Search missing results


We’re trying to make an Embedded Timeline widget for our website and are having troubles. It seems that the Search API used by the timeline is not returning the same results as the search field on the Twitter homepage. We configured a widget from our account settings page to display tweets matching the search query “#somehashtag OR @someuser”. The live preview in the configuration page shows only one tweet, as does the widget when embedded in our website, even though the same query string used in the search field of the Twitter homepage results in a long list of lovely tweets that we would love to showcase on our website.
Is this indicative of a known mis-configuration? We can see that there are some recent issues that have been raised about something that sounds very similar to this, but (as of writing this) those issues are all closed. We also read the ‘Embedded Timelines Most Frequent Problems (and their solution)’ post and (the first few pages of) the ‘Embedded Timelines Questions’ post but nothing there seems to apply here.
Can anyone help us? Would it help to see the exact search results and a live demo of the widget?
Thank you for your time.