Not every key is this bad, only some, but for $200, I feel like they should not have a saw tooth edge.
Every key has this manufacturing defect. Most key sets I have also have a similar bump, but they are on the bottom, not the back. I have a prime_e, and I use 2 keys flipped backwards (backspace and space bar), so I have these defects staring at me. If it was a less pricey set I would not mind, but for the price (and the almost 2 year wait) I was expecting more.
Those aren't manufacturing defects.
They are spruemarks from the molds and they are completely normal for doubleshot keycap sets.
And there's no way to get rid of them since the doubleshot manufacturing process requires them.
The reason that they are on the bottom of some cheaper sets is because those are usually dyesub PBT.
On dyesub caps the location of the mold sprue doesn't matter. For doubleshot it does.
And honestly:
A rough underside of the keycap is not a quality indicator.
Nobody is going to look under his keycaps...