Is it just on the one side, the bottom end of the bait near the sprue hole area? The 3.85 get this also but it is not very pronounced. Not enough to really notice until you start looking. Once you look, you see it is every bait.
Wish I could help. When I use the twinjector, the dent is there but extremely tiny.
Think it is an air bubble getting trapped there but not sure how to get rid of it without another vent.
Jim