Being anal-retentive I've always deprime before wet tumbling. Something about everything being nice and shiny.
this time I'm swamped with brass (I clean brass for a number of fellow cowboy shooters) I decided to skip the depriming part . . .
everything was great--brass was nice and shiny, clean in and out . . .
but after the usual amount of time in the Texas Sun I deprimed a few and found the primer pocket was still wet! Oh, no Mr. Bill! not good at all
so a trip through the press to deprime and back in the Sun--all is right with the world
now I'm guessing drying for a longer time or using an oven or such might solve this problem but I'm happy to return to my previous method.
I can deprime about 15-20 pieces of brass a minute so the amount of time is not significant in the long run.
Even a failed experiment teaches us something