Weird, but I think I fixed it. I had originally set the sequence for a 10 minute loop, but decided that a 3 minute loop was fine. I had changed the sequence length in settings, but didn't worry about the timings that were beyond the 3 minutes (which it wouldn't let me edit because the timing was shortened anyway). I decided to fix this by extending it to 10 minutes again and removing the light info, hen changing it back to 3 minutes. Not sure why, but it seems to have fixed it. Thanks everyone for your help! I'm really enjoying Xlights and can't wait until next year!