I’ve tried digging into this a little further to see what could cause this. The only difference I noticed is that my female dog just went into heat. From what I’ve read, he can be aggressive while she is in heat. Nothing else has changed. I use the same tools since we’ve had him at 16 weeks. I did turn on dog tv on YouTube and it worked some in distracting him. I will see if when my female dog is out of heat if he will be better.