Windows AVG wrong result for NULLs #22138

> SELECT i,AVG(v) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) FROM (VALUES(1,1),(2,2),(3,NULL),(4,NULL)) t(i,v);
+---+-----------------------------------------------------------------------------------------+
| i | avg(t.v) ORDER BY [t.i ASC NULLS LAST] ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING |
+---+-----------------------------------------------------------------------------------------+
| 1 | 1.5                                                                                     |
| 2 | 2.0                                                                                     |
| 3 | NaN                                                                                     |
| 4 | NaN                                                                                     |
+---+-----------------------------------------------------------------------------------------+

D SELECT i,AVG(v) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) FROM (VALUES(1,1),(2,2),(3,NULL),(4,NULL)) t(i,v);
┌───────┬──────────────────────────────────────────────────────────────────────┐
│   i   │ avg(v) OVER (ORDER BY i ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOL…  │
│ int32 │                                double                                │
├───────┼──────────────────────────────────────────────────────────────────────┤
│     1 │                                                                  1.5 │
│     2 │                                                                  2.0 │
│     3 │                                                                      │
│     4 │                                                                      │
└───────┴──────────────────────────────────────────────────────────────────────┘