The yields dropped a lot due to the fact that Lido reduced the LDO rewards for the stMATIC farms. This likely resulted in fewer votes this week, leading to a decrease in yields. It is important to stay up-to-date with the latest developments in stMATIC farming to ensure that you are taking advantage of the highest possible yields. Additionally, it is important to be aware of the voting rewards and the staking rewards that are available to maximize your returns.