Are some bulbs more equal than others?

I’ve just fitted some small rear indicators to my M900, now the indicators front & rear are flashing more quickly, (as though I had fitted LED’s without resistors), the indicators are cheap Chinese ones that usually earth to the frame, I fitted identical ones on my Scrambler and added a negative terminal inside the indicator bodies, they work fine, on the Monster I have taken the original plastic mounting bracket off and added a steel bracket, I’ve then connected the negative indicator wires from the loom to a single bolt on the bracket and fitted the indicators to the same bracket (with the live wires from the loom connected to the bulbs), I’ve made sure there is metal to metal contact between the bracket and indicator bodies, but I have this fast flashing issue, the front indicators are still standard.
Could it be the bulbs in the Chinese indicators are of a different resistance to the bulbs in the Ducati front indicators and it’s confusing the flasher unit?, or do I have a bad earth?, all ideas gratefully received, thanks Mark.