No shares have occurred in your selected time range.You may have a post with thousands of shares, but if they happened two months ago when the post was new, then none have occurred in the past 14 days, which is Filament's default date range, it will still show zeros.
Twitter shut down their Share Count APIThis makes us very sad. Back on November 20, 2014, Twitter shut down the Sharing Counts API. You can learn more about that here. This affects all sharing bars uniformly, not just Flare or Filament Pro.
Google+ only counts the "+1" actionIf someone posts your content to G+, Filament Pro is looking for the "+1" activity, which is the only activity the G+ network will allow us to query for. Often times publishers will promote their own content on G+ and expect to see a "1" in the early share counts, but this is not the case unless it has be "Plus one'd" since the time it was initially shared.
And lastly, you may have gotten a share or two on a post that didn't get any traffic. Filament will only recored and calculate engagement data for URL's that get at least 10 visits over a 24 hour period, so things like this happen on occasion. In general, if you have inconsistent traffic and teeter around that threshold, Filament may experience intermittent gaps in data since the sample size it too small to pull out meaningful insights.