Multitrack Recording: Inputs 1/2/3 went to Stereo Output not individual

Hey folks. So I did my first recording at my bands gig this past weekend. after the first Set I paused the recording. Set1-The first 3 inputs did not record to their respective tracks. apparently they ended up on the Stereo Pair combining the vocal inputs. Looks like they ended up on 17/18? Oddly, with making no changes and resuming the recording, Set 2 all channels recorded independently, as expected. I’m fairly confounded. Yes, I still have a lot to learn about this mixer (QU16). Thoughts? and Thanks for any suggestions.