It looks like someone at the factory had to rework it. If the automated soldering process produces a defect, rather than scrapping everything, a human fixes the mistake. This is called a rework. The person probably does one board every 20 seconds, or something crazy, so the quality is expectedly poor.
What is your concern? Does it not work?
Watch this crazy soldering speed:
http://www.youtube.com/wa...0E8WeEUVM&t=22m35sIt's not possible to produce quality solder joints at that speed (soldering iron way too hot, flux burns too much or too soon, increased thermal stress, burned crystalized solder, cold solder joints with poor penetration, etcetera), but it works good enough.
The soldering in your picture indicates that the soldering was done too quickly and didn't have time to melt down and flow evenly; but that's the expected result of budget mass manufacturing.
post edited by ty_ger07 - 2020/06/26 21:59:26