Ok, I had to ask. ;) Especially for pHats that come with the header not soldered on. Everything except the Zero comes with the GPIO header pre soldered. I wouldn’t suspect an issue that way, unless you see an obvious solder bridge. It could be the Pi, but a soldering issue is , IMHO, unlikely. It could be that the first automation pHat has a fault that did something to the Pi? Just guessing really though. Do you have another different pHat or Hat to try on that Pi? Any Pi with a 40 pin GPIO can be used to test those pHats. A+, B+, Zero etc.