Regression: The ANY_VALUE aggregate function always returns NULL

[sim1984]

I can't say exactly when it started, but everything definitely worked before.

SQL> show version;
ISQL Version: WI-T6.0.0.1367 Firebird 6.0 2a02c8c
Server version:
Firebird/Windows/AMD/Intel/x64 (access method), version "WI-T6.0.0.1367 Firebird 6.0 2a02c8c"
Firebird/Windows/AMD/Intel/x64 (remote server), version "WI-T6.0.0.1367 Firebird 6.0 2a02c8c/tcp (DESKTOP-MCH5AOF)/P20:C"
Firebird/Windows/AMD/Intel/x64 (remote interface), version "WI-T6.0.0.1367 Firebird 6.0 2a02c8c/tcp (DESKTOP-MCH5AOF)/P20:C"
on disk structure version 14.0

select
  emp_no,
  min(first_name) as first_name_min,
  any_value(first_name) as first_name_any
from employee
group by emp_no
fetch first 5 rows only;

 EMP_NO FIRST_NAME_MIN  FIRST_NAME_ANY
======= =============== ===============
      2 Robert          <null>
      4 Bruce           <null>
      5 Kim             <null>
      8 Leslie          <null>
      9 Phil            <null>