We recently had some boards returned that have me stumped. Word was QFP pins were coming out of the solder in the field. Upon inspection it was true!! If you press gently on the pins they SLIDE out of the joint. The joints look good, shiny ect but it is like clay???? To make matters worse it is only in one location on every board the upper right side of each QFP. Never seen this in 20 yrs!!