With the new update it came some kind of changes on object’s variables.
The point is, every time you want to make a local change in an object’s variables it’s a mess. It jumps from the input field (text, number) to anywhere else and mess up all the editor’s layout.
It seems the field input selects not only that field but the entire variable field and whatever you put on there is taken as a shorcut.
Procedure to replicate:
Make an object, set some default variables to this object.
On the scene editor, insert this object.
Select the object and try to change any of the variables on the object’s properties by selecting the respective field and start writing.
In fact this problem is not new and is already known by developers. Look at this other thread about it and the link that BWPanda shared: Editing first value of Instance Variable