Service with refresh function called by thread hangs on occasion

I have a service that needs to poll values in the background and therefore cannot wait for the next event to come in from a client. So I created another thread that calls a refresh function once a second, similar to this using zbus 2.0.0-beta:

use std::convert::TryInto;
use std::error::Error;
use zbus::{dbus_interface, fdo};

struct Greeter {
    count: u64,
}

#[dbus_interface(name = "org.zbus.MyGreeter1")]
impl Greeter {
    fn refresh(&mut self) {
        self.count += 1;
    }

    #[dbus_interface(property)]
    fn count(&self) -> u64 {
        self.count
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    let connection = zbus::Connection::new_session()?;
    fdo::DBusProxy::new(&connection)?.request_name(
        "org.zbus.MyGreeter",
        fdo::RequestNameFlags::ReplaceExisting.into(),
    )?;

    let mut object_server = zbus::ObjectServer::new(&connection);
    let greeter = Greeter { count: 0 };
    object_server.at(&"/org/zbus/MyGreeter".try_into()?, greeter)?;

    let _t = std::thread::spawn(move || loop {
        std::thread::sleep(std::time::Duration::from_secs(1));
        connection
            .call_method(
                Some("org.zbus.MyGreeter"),
                "/org/zbus/MyGreeter",
                Some("org.zbus.MyGreeter1"),
                "Refresh",
                &(),
            )
            .unwrap();
    });

    loop {
        if let Err(err) = object_server.try_handle_next() {
            eprintln!("{}", err);
        }
    }
}

To get the hangs to happen (or to make them noticeable?), run for example:

$ for i in $(seq 1000); do busctl --user get-property org.zbus.MyGreeter /org/zbus/MyGreeter org.zbus.MyGreeter1 Count; done
...
t 12
t 12
t 12
t 12
t 12
Failed to get property Count on interface org.zbus.MyGreeter1: Connection timed out
t 13
t 13
t 13
t 13
t 13
t 13
t 13
...

I could not get this to happen if I comment out the thread in the main function.