DIP soldering blowholes is also called pinholes in China PCBA community. It is a very common defect in DIP producing, if we don’t fix it, there will be a serious risk.

First risk is short soldering. It is small pin hole visible, but under it, maybe a big space inside solder point. This short soldering will increase the contact resist, get weaker electricity function, temperature may increase higher than expected after long time working. Finally it may get open circuit.