GstBlur raise core dumped error

Hello, I just tried to run the gst blur example. Simply running a gst-inspect-1.0 raises a core dump error. I even commented the part of the code that performs the actual transformation. It seems that the problem is caused by how properties are defined. Code to reproduce:
import logging
import timeit
import traceback
from typing import Tuple
import time
import cv2
import numpy as np

from gi.repository import Gst, GObject, GLib, GstBase

Gst.init(None)

DEFAULT_KERNEL_SIZE = 3
DEFAULT_SIGMA_X = 1.0
DEFAULT_SIGMA_Y = 1.0

def gaussian_blur(img: np.ndarray, kernel_size: int = 3, sigma: Tuple[int, int] = (1, 1)) -> np.ndarray:
    """ Blurs image
    :param img: [height, width, channels >= 3]
    :param kernel_size:
    :param sigma: (int, int)
    """
    sigmaX, sigmaY = sigma
    return cv2.GaussianBlur(img, (kernel_size, kernel_size), sigmaX=sigmaX, sigmaY=sigmaY)

FORMATS = "{RGBx,BGRx,xRGB,xBGR,RGBA,BGRA,ARGB,ABGR,RGB,BGR}"

class GstGaussianBlur(GstBase.BaseTransform):

    GST_PLUGIN_NAME = 'gaussian_blur'

    __gstmetadata__ = ("GaussianBlur",  # Name
                       "Filter",   # Transform
                       "Apply Gaussian Blur to Buffer",  # Description
                       "Taras Lishchenko <taras at lifestyletransfer dot com>")  # Author

    __gsttemplates__ = (Gst.PadTemplate.new("src",
                                            Gst.PadDirection.SRC,
                                            Gst.PadPresence.ALWAYS,
                                            # Set to RGB format
                                            Gst.Caps.from_string(f"video/x-raw,format={FORMATS}")),
                        Gst.PadTemplate.new("sink",
                                            Gst.PadDirection.SINK,
                                            Gst.PadPresence.ALWAYS,
                                            # Set to RGB format
                                            Gst.Caps.from_string(f"video/x-raw,format={FORMATS}")))

    # Explanation: https://python-gtk-3-tutorial.readthedocs.io/en/latest/objects.html#GObject.GObject.__gproperties__
    # Example: https://python-gtk-3-tutorial.readthedocs.io/en/latest/objects.html#properties
    __gproperties__ = {

        # Parameters from cv2.gaussian_blur
        # https://docs.opencv.org/3.0-beta/modules/imgproc/doc/filtering.html#gaussianblur
        "kernel": (GObject.TYPE_INT64,  # type
                   "Kernel Size",  # nick
                   "Gaussian Kernel Size",  # blurb
                   1,  # min
                   GLib.MAXINT,  # max
                   DEFAULT_KERNEL_SIZE,  # default
                   GObject.ParamFlags.READWRITE  # flags
                   ),

        # https://lazka.github.io/pgi-docs/GLib-2.0/constants.html#GLib.MAXFLOAT
        "sigmaX": (GObject.TYPE_FLOAT,
                   "Standart deviation in X",
                   "Gaussian kernel standard deviation in X direction",
                   1.0,  # min
                   GLib.MAXFLOAT,  # max
                   DEFAULT_SIGMA_X,  # default
                   GObject.ParamFlags.READWRITE
                   ),

        "sigmaY": (GObject.TYPE_FLOAT,
                   "Standart deviation in Y",
                   "Gaussian kernel standard deviation in Y direction",
                   1.0,  # min
                   GLib.MAXFLOAT,  # max
                   DEFAULT_SIGMA_Y,  # default
                   GObject.ParamFlags.READWRITE
                   ),
    }

    def __init__(self):

        super(GstGaussianBlur, self).__init__()

        # Initialize properties before Base Class initialization
        self.kernel_size = DEFAULT_KERNEL_SIZE
        self.sigma_x = DEFAULT_SIGMA_X
        self.sigma_y = DEFAULT_SIGMA_Y

    def do_get_property(self, prop: GObject.GParamSpec):
        if prop.name == 'kernel':
            return self.kernel_size
        elif prop.name == 'sigmaX':
            return self.sigma_x
        elif prop.name == 'sigmaY':
            return self.sigma_y
        else:
            raise AttributeError('unknown property %s' % prop.name)

    def do_set_property(self, prop: GObject.GParamSpec, value):
        if prop.name == 'kernel':
            self.kernel_size = value
        elif prop.name == 'sigmaX':
            self.sigma_x = value
        elif prop.name == 'sigmaY':
            self.sigma_y = value
        else:
            raise AttributeError('unknown property %s' % prop.name)

    def do_transform_ip(self, buffer: Gst.Buffer) -> Gst.FlowReturn:
        try:
            pass
        except Exception as e:
            logging.error(e)

        return Gst.FlowReturn.OK

# Required for registering plugin dynamically
# Explained:
# http://lifestyletransfer.com/how-to-write-gstreamer-plugin-with-python/
GObject.type_register(GstGaussianBlur)
__gstelementfactory__ = (GstGaussianBlur.GST_PLUGIN_NAME,
                         Gst.Rank.NONE, GstGaussianBlur)

if __name__ == "__main__":
    import os
    folder = os.path.dirname(__file__).replace("/python", "").replace("//", "/")

    command = f"GST_PLUGIN_PATH=$GST_PLUGIN_PATH:{folder} gst-inspect-1.0 {GstGaussianBlur.GST_PLUGIN_NAME}"
    print(command)
    os.system(command)
The code executes normally but it returns a core dump after printing the output of the get-inspect-1.0.
I am using GStreamer 1.14.5.
jackersson / gst-python-plugins

GstBlur raise core dumped error #12
