diff --git a/app/vmselect/promql/eval.go b/app/vmselect/promql/eval.go
index f0ba9dca1..21afcedbe 100644
--- a/app/vmselect/promql/eval.go
+++ b/app/vmselect/promql/eval.go
@@ -1149,7 +1149,15 @@ func evalInstantRollup(qt *querytracer.Tracer, ec *EvalConfig, funcName string,
 			},
 		}
 		return evalExpr(qt, ec, be)
-	case "count_over_time", "sum_over_time", "increase":
+	case
+		"count_eq_over_time",
+		"count_gt_over_time",
+		"count_le_over_time",
+		"count_ne_over_time",
+		"count_over_time",
+		"increase",
+		"increase_pure",
+		"sum_over_time":
 		if iafc != nil && strings.ToLower(iafc.ae.Name) != "sum" {
 			qt.Printf("do not apply instant rollup optimization for non-sum incremental aggregate %s()", iafc.ae.Name)
 			return evalAt(qt, timestamp, window)
diff --git a/app/vmselect/promql/rollup_result_cache.go b/app/vmselect/promql/rollup_result_cache.go
index d47490e4a..8a370bef1 100644
--- a/app/vmselect/promql/rollup_result_cache.go
+++ b/app/vmselect/promql/rollup_result_cache.go
@@ -625,7 +625,8 @@ func mergeTimeseries(qt *querytracer.Tracer, a, b []*timeseries, bStart int64, e
 		}
 		tmp.Values = append(tmp.Values, tsB.Values...)
 		if len(tmp.Values) != len(tmp.Timestamps) {
-			logger.Panicf("BUG: unexpected values after merging new values; got %d; want %d", len(tmp.Values), len(tmp.Timestamps))
+			logger.Panicf("BUG: unexpected values after merging new values; got %d; want %d; len(a.Values)=%d; len(b.Values)=%d",
+				len(tmp.Values), len(tmp.Timestamps), len(tsA.Values), len(tsB.Values))
 		}
 		rvs = append(rvs, &tmp)
 	}