Vivoactive 5 - Simple test watch face reverted to another one overnight

Hello,

I made a simple test watch face - the stock "watch face" project with an extra field for HR and a couple of custom fonts:

import Toybox.Graphics;
import Toybox.Lang;
import Toybox.System;
import Toybox.WatchUi;
import Toybox.Activity;

(:background)
class Watchface3View extends WatchUi.WatchFace {

    protected var dimmed;
    protected var width;
    protected var height;

    function initialize() {
        WatchFace.initialize();
        self.dimmed = false;
        self.width = 0;
        self.height = 0;
    }

    // Load your resources here
    function onLayout(dc as Dc) as Void {
        setLayout(Rez.Layouts.WatchFace(dc));
        self.width = dc.getWidth();
        self.height = dc.getHeight();
        System.println("Screen size " + self.width + " x " + self.height);
    }

    function onShow() as Void { }

    // Update the view
    function onUpdate(dc as Dc) as Void {

        var timeField = View.findDrawableById("time") as Text;
        var miscField = View.findDrawableById("misc") as Text;

        //
        var time = System.getClockTime();
        var hour = time.hour;
        if (! System.getDeviceSettings().is24Hour)
        {
            hour = (hour + 23) % 12 + 1;
        }
        var timeStr = Lang.format("$1$:$2$", [ hour, time.min.format("%02d") ]);
        timeField.setText(timeStr);

        //
        var sysStats = System.getSystemStats();
        var miscStr = "";

        if (sysStats.charging)
        {
            miscStr += ";";
        }
        else
        {
            var hr = Activity.getActivityInfo().currentHeartRate;
            miscStr += hr ? hr : "-";
        }
        miscField.setText(miscStr);

        dc.setAntiAlias(true);
        View.onUpdate(dc);
    }

    function onHide() as Void { }

    function onExitSleep() as Void {
        self.dimmed = false;
        self.requestUpdate();
    }

    function onEnterSleep() as Void {
        self.dimmed = true;
        self.requestUpdate();
    }
}

Nothing complicated. layout.xml has a single <layout> with two <label>s.

Built it for Vivoactive 5, put it on the watch, confirmed it worked as expected, then went to bed. Woke up today and the face is replaced by the one I had on before.

Any ideas what happened and why ?

Thanks !