Answer:
The sugar crystals recrystallises, and settles at the bottom of the container especially if the temperature of the mixture cools down gradually with time when left undisturbed.
Step-by-step explanation:
Solubility is the ability of some solids (solute) to dissolve in a liquid (solute) forming a solution. It depends on temperature, amount of solute to solvent etc.
In some cases, leaving the product undisturbed over time can revert the process, forcing the solid to recrystallise out of the solvent.