[twitter-dev] Geocoding distance gives different results?

Hello,

Is anybody able to help me overcome this problem;

I have a tweet posted with a geo tag. The following search gives me a
good result:
http://search.twitter.com/search.json?geocode=53.06871686402068,5.530435206584228,2km&rpp=100&callback=?&result_type=recent&q=bedankt

But, when i increase the distance to 9 km the results are gone
http://search.twitter.com/search.json?geocode=53.06871686402068,5.530435206584228,9km&rpp=100&callback=?&result_type=recent&q=bedankt

Now, when i pass around 22km the result appears again
http://search.twitter.com/search.json?geocode=53.06871686402068,5.530435206584228,22.3km&rpp=100&callback=?&result_type=recent&q=bedankt

(amongst others, use the id 72725900311011328 to find it again)

Now, is there a way to fix this issue?

Thanks in advance.

--
Twitter developer documentation and resources: https://dev.twitter.com/doc
API updates via Twitter: https://twitter.com/twitterapi
Issues/Enhancements Tracker: https://code.google.com/p/twitter-api/issues/list
Change your membership to this group: https://groups.google.com/forum/#!forum/twitter-development-talk