It better not!
We just recently added an additional seal into the solids bin so it should not leak at all. We can fill the entire solids bin full of water and if we agitate it full of water without leaking.
The medium in the bin should absorb excess urine first so you shouldn't have much urine in the solids bin let alone the whole bin.
If you have enough liquid in the solids bin for to to be raised up to the agitator, then there is a something wrong and please reach out to us!