Muzzleloader funny fire...?

Yep. Clean your breach plug flash hole and check those powder pellets for moisture saturation. Also check your primers for full ignition burn by simply cleaning your plug, inserting it back in the gun, load a primer and fire in a safe direction (without) the power pellets of course. It will also help to finish cleaning your plug on what you might have missed. Thorough cleaning is prevented maintenance in a muzzle loader (Always). And a little (Antiseize) on the plug threads will insure backout in case of rust build up after set up. Your primers or pellets are most likely your cause.