Oh, so that's how the last few seasons have looked so ridiculously good (and consistent)! "Black magic" problem: solved :PBy weekly do you mean a long running series and not one that just runs for 13 or so episodes?
Pokemon at one point had animation for episodes starting something like 8 or 9 months ahead of when they aired. It's around 6 months now though, which is still crazy good.
For comparison Super season 2 had animation start 4 months ahead of when the first episode airs, which is pretty great, but not ridiculous like Pokemon.