Submitted by WatchPug
https://github.com/code-423n4/2022-01-sandclock/blob/a90ad3824955327597be00bb0bd183a9c228a4fb/sandclock/contracts/Vault.sol#L290-L293
As a function that many other functions depended on, totalUnderlyingMinusSponsored() can revert on underflow when  sponsorAmount > totalUnderlying() which is possible and has been considered elsewhere in this contract:
https://github.com/code-423n4/2022-01-sandclock/blob/a90ad3824955327597be00bb0bd183a9c228a4fb/sandclock/contracts/Vault.sol#L390-L392
Change to:
naps62 (Sandclock) confirmed
