I recently discovered that libgstpython.so was incorrectly searching for python modules. Its last search location (on a CentOS 8 system) should have been '/usr/lib64/gstreamer-1.0/python' but it was instead searching in 'lib64/gstreamer-1.0/python'
I tracked this to the top level meson.build for gst-python and the creation of config.h. The meson variable 'libdir' holds only the final component of the libdir path, not the entire path as the meson code assumed.