RE: Will keeping a muzzleloader loaded cause any problems?
If your using a cap instead of a primer, change the CAP a couple of times throughout the day. It is my belief that the caps are responsible for the majority of misfires. Some are bad, right out of the can, and condensation as simple as from bringing cold rifle into warm car can be enough to foul it. Caps are so inexpensive, and I learned the hard way more than once when I shot traditional.
I hunt with ducktape over the end of my barrel of my Encore, and have left a load in for more than a few days, with no problems. You must, however always be aware of the fact that it is still loaded. That's why it is so important to score your rod where it exits the barrel, when there is a load in. Hate to have you put ANOTHER load into an already loaded barrel. Don't laugh, it happens!