Typically there are resistive heating elements in each end of the tube, when powered they heat up... "boiling off" some of the electrons causing the gas to ionize.
Once the gas is ionized the an electrical arc can flow from one side to the other, the flowing charged particles excites some of the mercury which partially vaporizes and starts the illumination process
This sort of gas discharge has a peculiar and problematic quality, If the current isn't carefully controlled, it will continually increase, and possibly explode the light fixture or maybe cause burn through... that I dont know
In a gas discharge, such as a fluorescent lamp, current causes resistance to decrease. This is because as more electrons and ions flow through a particular area, they bump into more atoms, which frees up electrons, creating more charged particles. In this way, current will climb on its own in a gas discharge, as long as there is adequate voltage If the current in a fluorescent light isn't controlled, it can blow out the various electrical components.
A fluorescent lamp's ballast works to control this... this is where the bulit in (if so equipped) ballast protection circuits come into play...
Now i dont know if these protection circuits are a common feature in your specific power compacts... but based upon my limited knowledge this is something i would ask the vendor about... and if it is a case of the cathode resting against the glass then I would have to question their quality control... regardless of source or reputation.
Av