m4 fails to expand macros after changequote

Here is a minimal example that demonstrates the problem:

   changequote({,})dnl
   define(P1, {changequote([,])`}$[]1{'changequote()})dnl
   changequote()dnl
   define(`foo', `$1 is not P1')dnl
   foo(`bar')

Running this example with GNU m4:

   theon$ m4 --version
   m4 (GNU M4) 1.4.19
   Copyright (C) 2021 Free Software Foundation, Inc.
   License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
   This is free software: you are free to change and redistribute it.
   There is NO WARRANTY, to the extent permitted by law.

   Written by René Seindal.
   theon$ m4 bug.m4
   foo(`bar')
   theon$ 

In comparison, running this with Solaris 11.4 m4:

   theon$ /usr/bin/m4 bug.m4
   bar is not `$1'
   theon$ 

Thanks & kind regards, Andreas F. Borchert

-- 
Dr. Andreas F. Borchert,  Institut für Numerische Mathematik, Universität Ulm
Helmholtzstr. 20, 89081 Ulm, +49 7315023572 https://mathematik.uni-ulm.de/afb