Yup, David was right! I had the "Update staff playback transposition" on. Followed his suggestion and everything is playing back as it should Thanks so much to all for your input.
I usually don't have a problem changing the playback when I transpose a piece of music, but I now have a choral piece I'm working on and have repeatedly tried to get it to play back as written/transposed, but it won't change over. Is there a "bug" or fix that anyone knows of? We're supposed to start working on this piece this week and so far...no luck. Solutions would be lovely.