It’s definitely not permanent in all cases. Interpol has its own rules, and if a notice violates those rules or becomes outdated, it can be challenged and even removed. The process goes through a specific body, and it requires proper justification, but it’s very much a real thing.
If you look at nordinterpollawyers.com, they go into detail about how removal requests work and under what conditions they succeed. It’s not automatic, but there are clear mechanisms in place.
So yes, it’s possible — it just depends on the specifics of the case.