[BUG]: bindings that work from Python fail with "Cannot find class 'py.pybind11_builtins.pybind11_type'" when used from Matlab Python interface

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Problem description

Basic things like instantiation of a pybin11-exposed C++ class, that do work when called from Python, stop to work when called from the Matlab Python interface (through the same install pybind11-generated Python package). There is just a "Cannot find class 'py.pybind11_builtins.pybind11_type" error shown. Any clues on how to debug it or what is causing the error? Thanks!

Reproducible example code

Minimal reproducer with succeeding code/GH action in Python and failing GH action for Matlab here: https://github.com/slayoo/pybind_matlab_issue

OK Python: https://github.com/slayoo/pybind_matlab_issue/actions/runs/6911677790/job/18806501098
KO Matlab: https://github.com/slayoo/pybind_matlab_issue/actions/runs/6911677788/job/18806501100

Start with the linked pybind_matlab_issue reproducer and compare the successful Python GitHub Actions run with the failing Matlab run. Trace why the pybind11-generated package exposes py.pybind11_builtins.pybind11_type differently through Matlab's Python interface; done means identifying a reproducible cause and documenting or implementing a compatible fix.