The UBA2211 and UBA2213 have capacitive mode protection. Capacitive mode will occur if the lamp voltage increases due to end of life or if the mains voltage drops way below its nominal value. Capacitive mode might damage the MOSFETs similar to inductor saturation. Before the resonant tank hits capacitive mode it will first get into hard switching as shown in the scope plot on this slide. The UBA2211 and UBA2213 will react to capacitive mode and hard switching by quickly increasing the operating frequency. The UBA2211 and UBA2213 also have over-temperature protection. If for whatever reason the silicon temperature rises above 175°C,  the IC switches off and only restarts when the temperature has dropped below 100°C.