Indeed, Otto, it’s merely a coincidence. Colombia is increasing imports from various countries, not just the USA.
All data from this link. The 2014 data only goes until October, so this decline might not be visible in the final results. As shown, the major beneficiaries since 2010 have been Mexico (which has a free trade agreement since 1995) and China (which lacks a free trade agreement), significantly more than the USA.
Trends in commodity prices and the evolution of Colombian access to consumer credit (particularly for Chinese products) likely play a larger role in this dynamic than trade agreements.