Summary

The bug was in the "YieldFacet" contract that allows VaultUser to easily deposit amount and automatically claimDittoMatchedReward

if (userReward > type(uint80).max) revert Errors.InvalidAmount();

must be

if (userReward > type(uint80).max)type(uint80).sub revert Errors.InvalidAmount();

Vulnerability Details

Impact

The impact is cause is underflow in an arithmetic operation which causes a revert in this line :
"userReward" can be bigger than "type(uint80)"

Tools Used

Manual check and vscode

Recommendations

The fix is simple

"userReward" must not be bigger than "type(uint80)"
in other words "type(uint80)" must be the max of itself and "userReward"