The timing is a bit awkward to begin with, since the lack of continuity around day 45/46 made us lose track of what day it actually is, and with a mix of European and American posts the timezones dilute day boundaries. So when you posted the oldest song on what might have been the 11th for you (no, I did not do the math), it was already the 12th here so our British members locked in on that and I followed suit, despite my math telling me it should have been day 48 already. So naturally, I posted my day 48 song one day after my day 47 song - but it was at a different time of the day and you had already caught up.
Next time we do this, we should either specify calendar days or agree on a timezone to avoid this, I guess. And one day appears to have been lost before the 45/46 break if my math works out.