gdb ignores set follow-fork-mode child

Hello,
I have NetBSD 10.1.
When I start gdb and issue command: set follow-fork-mode child
then gdb is still stepping through parent process after fork(), it 
ignored above command.

It is the same with both gdb which I have:
/usr/bin/gdb   11.0.50.20200914-git
/usr/pkg/bin/gdb 10.1 (package gdb-10.1nb6)

Does exist any trick how to force gdb to follow-fork-mode child ?

Peter