SDL_Mixer panning problems with looping sounds

I’m running into a problem with SDL_Mixer when using panning with looping
sounds. I’m writing a task that plays samples back in either the right or left
channel (like a hearing test). I’m using Mix_SetPanning to set the right/left
volume and Mix_PlayChannel to playback the clip. If I use -1 or 0 for loops in
Mix_PlayChannel, everything is fine. If I use loops>0 and play the clip, it
plays fine; however, the NEXT clip I play, regardless of number of loops or
setting the panning, plays back through both channels as if the panning effect
was unregistered. Any ideas? I’m using SDL_Mixer 1.2.7 under WinXP SP2.