Note: At the judges request here, this downgraded issue from the same warden has been included in this report for completeness.
The depletion of the yield buffer in the PrizeVault contract, leading to a state where (_totalAssets < totalDebt_) is short by a relatively insignificant figure that could be even larger than 1e5. This presents a vulnerability that could be exploited by savvy users to gain an unfair advantage in prize competitions.
In this scenario, the contracts logic prevents new deposits due to the lack of a yield buffer, intended to ensure the no loss principle for all depositors. However, a user could circumvent this safeguard by donating a minimal amount (e.g. 1 wei to any amount worth the venture) of assets to the contract, just enough to re-enable deposits. This action could allow the user to make a substantial new deposit, disproportionately increasing their share and, consequently, their chance of winning an impending grand prize, at minimal cost. This is particularly crucial when the yield vault is going to unexpectedly stop generating yield for quite a while.  
Consider the following steps for exploitation:
This strategy could be particularly appealing if the timing aligns with the accumulation of a substantial prize, allowing the user to maximize the odds of prize winning with minimal additional contribution to the prize vault.
I suggest a bot be set up for the prize vault owner to auto replenish the yield buffer when _totalAssets < totalDebt_ - 1 or nearing this condition jointly assisted/alerted by the emitted deposit event.
Timing
trmid (PoolTogether) acknowledged and commented:
hansfriese (judge) decreased severity to Low and commented:
Note: For full discussion, see here.
