diff --git a/cmd/root.go b/cmd/root.go
index 4cd05ff3..2adff188 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -270,6 +270,7 @@ var rootCmd = &cobra.Command{
 			if err := c.BuildReportConfig(); err != nil {
 				return err
 			}
+			r.Coverage.FlushBlockCoverages()
 			datastores := []datastore.Datastore{}
 			for _, s := range c.Report.Datastores {
 				d, err := datastore.New(ctx, s, c.Root())
diff --git a/pkg/coverage/coverage.go b/pkg/coverage/coverage.go
index 100916af..bb27970b 100644
--- a/pkg/coverage/coverage.go
+++ b/pkg/coverage/coverage.go
@@ -24,7 +24,7 @@ type FileCoverage struct {
 	File    string         `json:"file"`
 	Total   int            `json:"total"`
 	Covered int            `json:"covered"`
-	Blocks  BlockCoverages `json:"blocks"`
+	Blocks  BlockCoverages `json:"blocks,omitempty"`
 	cache   map[int]BlockCoverages
 }
 
@@ -63,6 +63,12 @@ func NewFileCoverage(file string) *FileCoverage {
 	}
 }
 
+func (c *Coverage) FlushBlockCoverages() {
+	for _, f := range c.Files {
+		f.Blocks = BlockCoverages{}
+	}
+}
+
 func (coverages FileCoverages) FindByFile(file string) (*FileCoverage, error) {
 	for _, c := range coverages {
 		if c.File == file {
diff --git a/report/report_test.go b/report/report_test.go
index 1261be0d..7979d4a5 100644
--- a/report/report_test.go
+++ b/report/report_test.go
@@ -37,6 +37,9 @@ func TestTable(t *testing.T) {
 		if got := r.Table(); got != tt.want {
 			t.Errorf("got\n%v\nwant\n%v", got, tt.want)
 		}
+		_ = r.String()
+		r.Coverage.FlushBlockCoverages()
+		_ = r.String()
 	}
 }