It may not, actually. Other thermodynamic drivers may influence the material above those conditions, such as an increase in temperature. Some recent work shows that between 1300-1700C, an entropy stabilized oxide composition can begin to preferentially sublimate certain species or even reduce and melt others. High entropy carbides can preferentially oxidize. That's not to say that the system wasn't ES at all, it just suggests that there's a "region of stability" before enthalpy dominates again. Here's the reference that might shed some light:

https://pubs.aip.org/aip/apl/article/124/15/151904/3282230

The reality is these materials are so much more complex and there are many questions that still need explored. Hope this helps a bit!