Vacuum metastability referenced in "Simplified chain inflation" and Hubble time

Hivoyer

In this paper http://power.itp.ac.cn/~huangqg/Publ...0inflation.pdf it is referenced(Ctrl+F 'with the lifetime of the metastable vacua much shorter than the Hubble time') that basically that is the time it takes for a vacuum phase transition to occur?Am I getting this right?By Hubble time do they mean 13.8 billion years?I'm kinda confused here,are they implying it's "due time" for a metastability event?