A little more explanation is required, since the boiling pot still needs to pass through room temperature on its way to freezing, and it’s not clear how at that point it has a head start on the other room temperature pot.
We did this in high school, and put 3 thermometers in both buckets. At the point when the water at the very bottom of the hot bucket reached ~6°C, the top of that bucket was still >60°C. This was in a 30cm tall 10 liter bucket, it really surprised us how strongly the water stratified. The top loses heat fast through evaporation, but the temperature of the water at the top does not fall very fast because the newly-cold water flows rapidly down the sides of the bucket. If you add constant mixing to both buckets, the hot one freezes slower than the room-temperature bucket.
If you want a very simple analogy, boiling water is strongly self stirring especially in a cold environment, whereas cold water in a cold environment does not self stir.
This effect is very old popular science filler material, and in the 80s there was possibly a Mr Wizard or similar TV episode where the effect was demonstrated by taking aquarium air tubing and an "empty" mustard squeeze bottle (only worked with one specific brand, plochman's mustard I think) and fill the "empty" mustard bottle such that you've made free yellow food coloring, then stick the aquarium hose in the clear bucket of freezing water and squirt in some mustard food coloring and watch how the convection currents in the previously hot container are huge and the water turns uniformly yellow in seconds whereas the previously cold water the yellow diluted mustard-water just sits there, pretty much. Its easy to use the hose and a stopwatch to try and quantify the currents. Now a days kids would probably use a smartphone camera or ipad and then use a video editing program to quantify the actual water current speeds vs time/location, but its easy to miss the important overall qualitative interpretation by trying too hard to generate too much quantitative information.
So, the answer to your question is "a really large number", but it's not obvious that Frozen 2 would have influenced them.
It was always a silly notion, especially when numbers like 30C - a dilution of one part in 10^60, or one molecule of the target substance in 3 × 10^34kg of water, after you understand what molecules are - were being thrown around, but there was at least a plausible explanation before, say, WW1.