Submitted by BowTiedOriole, also found by d3e4, McToady, slylandro_star, 0xmystery, ether_sky, amaechieth, 0xPhantom, wangxx2026, nuthan2x, zxriptor, Bobface, Krace, hals, cats, EV_om, and AlexCzm
https://github.com/code-423n4/2024-01-curves/blob/main/contracts/FeeSplitter.sol#L90 
https://github.com/code-423n4/2024-01-curves/blob/main/contracts/FeeSplitter.sol#L43-L46 
https://github.com/code-423n4/2024-01-curves/blob/main/contracts/Curves.sol#L248
FeeSplitter.addFees() reverts if the totalSupply of the token is 0. The total supply is calculated via the formula below:
Consider the following scenario:
Bobs transaction will revert because FeeSplitter.totalSupply() will return 0.
Check if the Curve contract balance matches the total supply, and if so, send the holder fee to the protocol.
Alternatively, you can call _transferFees prior to updating token balances and supply, but this will require reentrancy guards as well as other adjustments to the fee calculations.
andresaiello (Curves) confirmed
