Summary

Within ERC20 there are some that have a fee on transfer functionality, when the contest manager funds the pot using contestManager::fundContest, the function transfers from the manager to the contract the totalRewards amount, but doesn't check if the balance of the contract is equal to said amount after the transfer, if the used reward token has fee on transfer the amount in the contract will not be enough to cover the total of the rewards, making it imposible for the last players to claim their rewards.

Impact

Last player to claim their rewards will no be able to do so because of insufficient funds in the pot

Tools Used

Foundry and manual review

Recommendations

You may make a list of white listed tokens so that only allowed ERC20 can be used as pot rewards.