TNY286 as dimmable LED driver

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I am using a TNY286 to drive 3 power LED. I made a circuit with a shunt resistor and a LMV331 to use it as a current driver. however, I would like to dim the LEDs, therefore I am using an optocoupler on the EN/UV pin, where I apply a PWM. This is working fine until i set the PWM to 100%. The circuit hangs itself and I have to remove the power completely. Do you know why this happen? Do you have any recommendation to resolve this problem?
However whenn I put my ko sonde (about 14pF) between drain and source of the tny it is working perfectly.

Hi AR22,

Thank you for using Power Integration's product TinySwitch for your project. What does it mean when it hangs, is it completely turned off or is the light on/off at 100% PWM?

The 14pF might be suppressing the noise that triggers one of the protection of the TNY286. It acts as filter. Does this mean it is perfectly working at all PWM 10%-100% input?