must be doing something wrong?
Maybe, maybe not. A lot depends on what you do, and what you consider "soaked". If youre active, and the holster is truly and constantly soaked through, if youre gun doesnt show some rust, then youre definitely doing something right, and please tell us what youre doing. Ive carried SS guns in wet leather holsters too, and while better than blued, they always showed rust/corrosion at some point, especially at or under the grips, and on a couple of places on the slide.
For a good part of my life, I used to go through one out of two brand name leather holsters a year (last batch were a couple of Galco Royal Guards), and most of the problem for them came in the summer. Its hot and humid here in the summer, and once your holster is "soaked", its wet pretty much the rest of the summer, even when you try and rotate between a couple of them (leather doesnt dry out quickly on a good day or week). Add to that, sweating heavily all day, pretty much every day, and the gun is constantly wet and going down hill pretty quick if you dont do something. Even when you do, youre basically just trying to hold back the inevitable.
The two things that solved the problem for me initially, were kydex and hard chrome. My Commander in beautiful Colt blue, lasted less than a year in those Royal Guards, and then lasted 10+ years, in the same Blade Tech kydex holster, after it was hard chromed. Even then, I still got a powdery rust in the summer, around the inboard grip panel, the only part of the gun not protected by the holster. That Blade Tech holster basically saves the gun, and over time, it also will buy you another gun in what you save in buying leather holsters each year.
When I switched to SIG's and using the Blade Tech's, I had basically no problems at all, and the Glocks that replaced them, go without saying.