Two applications are fetching the same data from the cache and trying to modify the data.
This is only a problem if you are talking about the second level cache and the cache is distributed. Hibernate checks for changes in cached objects.
Hibernate firstlevel cache, we could not disable. second level only we are disabling.
Its not that normal to enable the second level cache. But like I said, unless your cache is distributed this is not an issue. When it comes to distributed cache, cache providers have a bunch of configuration options you can tweak.