[Possible Bug?] Failed Assert Is Being Ignored in Bindings

[xARTPOP]

I think I've found a bug but want to make sure I haven't overlooked something before opening a new issue. In my overloading of the operator[], I've got an assert to make sure the id being accessed isn't outside the bounds of the array. This works to stop the C++ code, but in Python, it gives no indication of the assert failure and still returns a value, though I'm not sure where this value is coming from. Below is a reproduction of this behavior.

#include <pybind11/pybind11.h>
#include <pybind11/operators.h>

#include <array>

class foo {
public:
        std::array<int, 4> data{1, 2, 3, 4};
        size_t size = 4;

        double operator[](const size_t idx) {
                assert(idx < this->size);
                return this->data[idx];
        }
};

namespace py = pybind11;

PYBIND11_MODULE(assert_issue, m) {
        py::class_<foo>(m, "foo")
                .def(py::init<>())
                .def("__getitem__", py::overload_cast<const size_t>(&foo::operator[]));
}

On the Python side, this code prints the following 10 values, despite the C++ assert failing for the last 6.

from assert_issue import foo

this_foo = foo()
for i in range(10):
    print(this_foo[i]) 

1.0, 2.0, 3.0, 4.0, 4.0, 0.0, 113.0, 0.0, 0.0, 0.0

The numbers printed for index 4-9 change on recompilation/rewriting of code, but I'm not sure what specifically they're accessing in memory to print out. Is this a bug I should open an issue for or have I overlooked something in the docs/my code that explains this behavior?