Any change in current that the flasher is designed for will cause the fast flash. Many reasons for incorrect current. If both left and right turn circuits have fast flash, it is not a bulb or it's a bulb on each side. If bulbs are all good, next is flasher, intermittent current or ground, switch.
I don't know how long ago "Day 1" was, or if it means Day 1 of your purchase of the truck, or some other Day 1. It may indicate someone originally used a wrong component. I see the flasher has been replaced. If the flasher type is the problem, and someone used the old flasher part number to get another, the fast flash would continue.
We can't say fog light uses more current, we don't know what bulb is in there.
