It seems that heat is an issue with UV LEDs, and hence they are not well suited for hotrods. If you use it until it is hot, you will damage the LED, especially when it is overdriven.
“LG parts must be derated starting at 25-30c – expecting the Convoy to reliably dissipate heat well enough for one of their UV LEDs driven at 5.8W is wishful thinking (IMHO).”
There is a derating curve shown in the AliExpress listing, 25C - 1500 mA, 60C - 700 mA, 85C - 100 mA. This is for ambient temperature, not LED temperature or flashlight body temperature.
S12 has some temperature protection, but probably not aggressive enough to save UV LEDs from heat damage.
I have no personal experience with this issue, does anyone know more?