This looks a lot like this issue:
https://github.com/mapnik/python-mapnik/issues/231
That was caused by boost-python not being built with the same Python
version.
Because the module still works with the default python the severity is
reduced. If this issue persists when python3.12 is the
Source: python-mapnik
Version: 1:0.0~20200224-7da019cf9-5
Severity: serious
Tags: upstream
Justification: makes the package in question unusable or mostly so
Dear Maintainer,
Importing the module with python3.12 results in a segfault:
$ python3.12 -c 'import mapnik'
Segmentation fault
$
