TRIAC controllers in these devices typically trigger near zero crossing. CFLs (and fluorescent fixtures) draw almost no current at zero cross because the voltage is too low to make the lamp conduct.
So the TRIAC gate is triggered at zero cross, but turns off (or sometimes never turns on) due to lack of holding current. Later in each cycle of mains voltage, the lamp is ready to accept current. But the TRIAC gate is no longer being driven.
It gets worse. Sometimes the TRIAC triggers and holds. This is on random cycles, and is really bad for the lamp (and controller).