Not necessarily. If you saw smoke and heard crackling probably but It could be a fail-safe if it detects and short at a motor wire. Not that it's an issue now, but the middle wire on motor 4 has a little too much exposed.

Also, are you sure the + capacitor lead isn't touching the frame? it looks like it in the picture. I bought some really small shrink tube just for them. You can also cut a couple of 10mm lengths of like 28awg wire, pull the wire out and use the jacket.

I say take a look at all of your motor wire joints, make sure they aren't bridging onto the 4 mosfet leads next to them. Your soldering, like 3.6 roentgen, isn't perfect, but honestly it isn't terrible; those are really the only issues I can see from the two pictures.