Charming,

It appears that the pin is heating more than the board, so it wins the tug of 
war for the solder.

The picture you sent (not attached on the listserver) shows a solid plane on 
the solder side of the board.  This is always more difficult to solder, since the 
heat  does not need to travel through holes to use the plane as a heatsink.  
You may need too slow down your conveyor to get these to solder properly.  
The thermal relief pattern shown in the picture appears to have quite a bit of 
copper on the conductive spokes,  to the point where there really isn't much 
relief  You should calculate the required trace width for the current in that pin, 
and reduce the spoke widths so that the total cross section of all of the 
spokes equals the cross section required if it were connected by a trace 
rather than a thermal relief pattern.  This may not completely solve the 
problem, because of the solder side plane, but it will help that individual pad to 
heat a bit more.

Pete

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