I have a code pen at https://codepen.io/ericg97477/pen/eYMJrqj demonstrating the issue.
If I drag the square polygon, I get two errors in the console...
L.Path.Drag.js:6 Uncaught TypeError: L.DomEvent.fakeStop is not a function
at i._onDragEnd (L.Path.Drag.js:6:3571)
at HTMLDocument.o (DomEvent.js:108:13)
L.Path.Drag.js:6 Uncaught TypeError: L.DomEvent.skipped is not a function
at i.<anonymous> (L.Path.Drag.js:6:3370)
I am not sure if this is a bug or something I am doing wrong.
I do note that at https://leafletjs.com/reference.html#domevent, it does not mention fakeStop or skipped methods.
Perhaps these were in older releases of leaflet...?