Query parameters sometimes are missing in href

My application is embedded in an iframe, I need to retrieve the url parameters.
I print out the url within the callback that executes when dcc.Location changes url. The main parts of my code are (I skip the definition of some variable for simplicity)

app = dash.Dash(__name__)
server = app.server
app.config["suppress_callback_exceptions"] = True
app.layout = page_builder.page_structure
    dash.dependencies.Output(presentation_constants.PAGE_CONTENTS, "children"),
    [dash.dependencies.Input(presentation_constants.URL, "href")],
def _my_page(href):
    if href is None:
        return DEFAULT_OUTPUT
    log.info(f"Starting with my page for href {href}")  # here I get the correct path but sometimes query parameters are missing!
    # ...

page_structure is defined as

page_structure = html.Div(
            id=pc.URL, refresh=False

Inspecting the iframe, I can see the correct path; the log in the callback reports the correct path, but the query parameter is stripped. Reloading the page in which the iframe is used, in the log I get the correct query parameters.
Do you see any evident reason for such behavior?