LED bulb can not start properly (BP2832 based)
A reasonable guess is that the electrolytic  capacitors have dried out a bit and the increased ESR (Equivalent Series Resistance) is causing some instability. 

The circuit is very compact and does not look particularly efficient, so the parts probably are running rather hot. The lifetime of an electrolytic cap at full rated temperature is only a few thousand hours (2000 for a low cost type). 

If you have an ESR meter, try removing the caps and testing them. Look up comparable size and voltage/capacitance rating parts and compare measured ESR to the specs. Incidentally, I suspect your value is incorrect on the 50V capacitor, since the size is similar to that of the 400V parts it is probably much higher in value.