Submitted by Lambda, also found by 0x29A
https://github.com/code-423n4/2022-07-fractional/blob/f862c14f86adf7de232cd4e9cca6b611e6023b98/src/modules/Migration.sol#L202
https://github.com/code-423n4/2022-07-fractional/blob/f862c14f86adf7de232cd4e9cca6b611e6023b98/src/modules/Migration.sol#L528
When proposal.totalFractions is equal to the total supply (meaning that all token holders want to participate in a migration), there is a division by zero in _calculateTotal.
In contrast to a buyout, where it does not make sense to initiate a buyout if all tokens are held (because there is a dedicated method for that), it does make sense to have a migration that all token holders join. Therefore, this case should be handled.
In such a case, redeem can be used instead of starting a buyout.
Ferret-san (Fractional) confirmed 
HardlyDifficult (judge) commented:
