I'm struggling to see how that could happen on a Juice...
There is a rise in the backspring, about where the dent is on your blade, but the raised are seems to run at a sort of "plateau" for over an inch, before it appears to drop back down. Because of that, you'd expect the damaged are to be a lot longer if striking the backspring was the problem.
The only way I could see a dent like that being formed would be if the blade was closing at an angle, rather than parallel to the spring. In turn, I can't see how the design would allow that to happen, unless the pivot-hole in the blade was off centre or the pins were bent or something. Weird huh?
I've just checked several of my Juices, especially the ones I use most, and can't see anything similar.
Which model of Juice is it ATT? I'll look and see if there's anything different about that specific model.