I had to go through with that spark and pop again. Maybe most simply disconnect the neg bat terminal and when connecting it, it's just a minor spark or no big deal.
Try removing the in line fuse, Im not sure if there is a lapse of time in order to get a much louder pop and good spark. If you wait at least 15 min. Try connecting that fuse again and let me know if it's not something to be concerned about. It also happens with the amp's ground too, I used just remove the fuse, but some metal scars were developing on the contacts from the sparks I had, I rather let the neg dist block take those inside the hole before I set the screw on the wire.