Submitted by rvierdiiev, also found by immeas, hansfriese, bin2chen, Lirios, ayeslick, jasonxiale, critical-or-high, mookimgo, Ruhum, hashminer0725, and hashminer0725
Anyone can reset fees to 0 value when Vault is deployed. As result protocol will stop collecting fees.
Anyone can call changeFees function in order to change fees variable to proposedFees.
https://github.com/code-423n4/2023-01-popcorn/blob/main/src/vault/Vault.sol#L540-L546
There is a check that should not allow anyone to call function before quitPeriod has passed after fees changing was proposed.
However function doesnt check that proposedFeeTime is not 0, so that means that after Vault has deployed, anyone can call this function and the check will pass.
That means that fees will be set to the proposedFees, which is 0.
As result protocol will stop collecting fees.
Use this test inside Vault.t.sol. Here you can see that no one proposed fee changing, but it was changed and set fees to 0.
VS Code
RedVeil (Popcorn) confirmed, but disagreed with severity 
LSDan (judge) decreased severity to Medium 
