diff --git a/app/vmselect/promql/rollup.go b/app/vmselect/promql/rollup.go
index c1e0cb622..b1f418ce0 100644
--- a/app/vmselect/promql/rollup.go
+++ b/app/vmselect/promql/rollup.go
@@ -170,6 +170,7 @@ var rollupFuncsCannotAdjustWindow = map[string]bool{
 	"ascent_over_time":    true,
 	"descent_over_time":   true,
 	"zscore_over_time":    true,
+	"first_over_time":     true,
 	"last_over_time":      true,
 }