First of all, LED bulbs usually are not dimmable or are cheap Chinese crap containing just a capacitor as a ballast.
Secondly if the load is reactive and mains voltage is 230V AC, MOC3021 is a very poor choice. It often triggers by by itself in such cases. MOC3051/3052 is much better. Thirdly, to cope with reactive load you need to use snubber circuit consisting of resistor and capacitor.
And lastly, post the schematic and what LED bulb you are using.