The sentence error lies in the phrase "has met yesterday". This is a grammatical issue involving the use of tense. The present perfect tense "has met" is used to describe actions that occurred at an indefinite time. However, the word "yesterday" specifies a definite past time. These two cannot logically coexist. To correct this, replace "has met" with the simple past "met," which is appropriate for an action that definitively took place in the past. Therefore, the corrected sentence should be: "The committee met yesterday to discuss the budget proposal."