diff --git a/internals/overlord/logstate/loki/loki_test.go b/internals/overlord/logstate/loki/loki_test.go
index 9a3a71f7b..e146e66c4 100644
--- a/internals/overlord/logstate/loki/loki_test.go
+++ b/internals/overlord/logstate/loki/loki_test.go
@@ -125,7 +125,7 @@ func (*suite) TestRequest(c *C) {
 
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		c.Assert(r.Method, Equals, http.MethodPost)
-		c.Assert(r.Header.Get("Content-Type"), Equals, "application/json")
+		c.Assert(r.Header.Get("Content-Type"), Equals, "application/json; charset=utf-8")
 
 		reqBody, err := io.ReadAll(r.Body)
 		c.Assert(err, IsNil)