Listener not found warning

[Darksymphony75]

Using Leaflet.Sleep with the latest leaflet.js (1.8.0). After I move the mouse over the map, all browsers throws a warning Listener not found in Events.js:180:10.

The Events.js is not physically present in my file structure, seems it is generated by leaflet itself and the console shows it's path as src/core/Events.js.

There might be some conflict between Leaflet.Sleep and the newest leaflet, because with older leaflet.js there is no warning.

Also when I remove Leaflet.Sleep from my webpage and use only leaflet.js, the warning is gone, so it is definitely caused by Leaflet.Sleep.

[Darksymphony75]

Leaflet.Sleep has many usages of off() after once(), which will always throw listener not found because once has already removed the listener. Can you please take a look?