What is the physical meaning of fact, that Reissner-Nordstrom black hole is thermodynamically unstable?

It is known, that Reissner-Nordstrom black hole is thermodynamically unstable [1].

• Does it mean, that there is no Reissner-Nordstrom black hole in physical world?


• Does it mean, that there may be phase transition?


• Does it mean, that it can be stable for enough long time?

[1] For example, arxiv.org/pdf/0812.1767v2.pdf pp.19-20.