Configure's conditional test output changes when changing software version

Question

I have an if clause inside a configure script that is behaving differently depending on the parameter (glib) that I pass to configure

In other words, if I pass

PKG_CONFIG_PATH=/media/34GB/Arquivos-de-Programas-Linux/Glib-2.67.4/lib/pkgconfig/ 

as parameter to configure, instead of:

PKG_CONFIG_PATH=/media/34GB/Arquivos-de-Programas-Linux/Glib-2.48.0/lib/pkgconfig/

configure behavior differs.

The first line I meet where such behavior differs it is:

if $PKG_CONFIG --atleast-version $min_glib_version $pkg_config_args; then

If I pass glib 2.48, it evaluates to true, and nothing happens inside the if clause. However, if instead I pass glib 2.67, it will evaluate to false and a variable "no_glib" is set to yes, instead of continue to be

no_glib=""

Ultimately, this will make Glib's detection to fail. The question is why?

I printed the value of all variables of the line:

if $PKG_CONFIG --atleast-version $min_glib_version $pkg_config_args; then

and they all match: $PKG_CONFIG,$min_glib_version and $pkg_config_args are equal with both Glibs:

$PKG_CONFIG = /usr/bin/pkg-config
$min_glib_version = 2.37.6
$pkg_config_args = glib-2.0 gobject-2.0 gmodule-no-export-2.0 gthread-2.0

So what might be happening?