While the devs may not have explicitly changed anything in code, the properties of the object are likely dynamic and there is an issue with what you're using to identify the object.
As for the alias itself changing, this is probably because you have automatically map objects turned which is creating a new mapping because the dynamic property has changed.
Can you provide more info about what properties you are using to identify the objects in your name mapping, and what the difference is from the first and second mapping? Without any other info any furthers attempts to debugs this would be shots in the dark.