Hi Bud
We buy what you're selling, when you say, "I suspect ... coo planarity of the connector during soldering (bending like banana) and that is why first or last leg is not soldered."
This component is probably acting like some BGA that curl at the corners during reflow. Where the differences in Cte of the materials of the component expand and contract at different rates. You can verify this by heating the component on a hot plate and taking a video of the movement of the component. For more insight, look here: http://www.cooksonsemi.com/tech_art/pdfs/Controlling%20Warpage.pdf
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