ORDER BY f1 WITH FILL, f2 WITH FILL always fills data only for one field which first in SELECT order and ignore fields order in ORDER BY clasue

How to reproduce

SELECT toDate(number*10*86400) AS d1, toDate(number*86400) AS d2, 'original' AS source
FROM numbers(10) WHERE number % 3 = 1
ORDER BY d2 WITH FILL, d1 WITH FILL;

have same result as

SELECT toDate(number*10*86400) AS d1, toDate(number*86400) AS d2, 'original' AS source
FROM numbers(10) WHERE number % 3 = 1
ORDER BY d1 WITH FILL, d2 WITH FILL,;

Expected behavior:
filled by d1 or by d2 according to ORDER BY field order

Actual behavior
always only d1 filled, and d2 always have default valu

• Which ClickHouse server version to use:
  docker 20.5.2.7
• Which interface to use, if matters
  Native