Let's go for example in https://it.wikivoyage.org/w/index.php?title=Siracusa&action=edit and click in the first line between the two joined words "Quickbar" and "City".
Now, clicking on the special char "À" we will obtain "QuickbarÀCity", but if we press backspace to delete the "À" and then clicking it again, this time we will obtain "QuickbarCÀity".

The same behaviour happens in it:w and have been tested by another user.

IE and Firefox works correctly.

Note: in general, more I delete with backspace and more the added char is located in the opposite side. It's like he consider the position of the cursor before the char deletion.