Proximity filter adds a 'and (0)' to the view sql even if unset

Issue Summary

We are using location views and have used a "Location: Distance / Proximity" as one of the filters, see attached 1.jpg. Even though the value is not set of the zipcode, it adds a additional "and (0)" to the view's sql, see below & 2.jpg.

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WHERE (node.type in ('listing_elite', 'listing_portfolio')) AND (node.status <> 0) AND (0)
ORDER BY node_title ASC

Some one please help.