Need some electrical advice!

You either want the Load dependant relay fitted OR the Resistors but you don't need both and that maybe your problem but I suspect not.
You need to check all your wiring front and rear has good connections and the LED indicators are wired with the correct polarity.
If there reversed they shouldn't work at all but check anyway.

Can't agree. At mine I'd added LED turn indicators first at front were installed with said extra resistors. Function were ok but an increased amount of flashsignals were already notable. Later I had installed also at the rear LED indicator with additional resistors and that hadnt worked well. Even with engine off they started flickering and flashing wildly and were unusable.
Just for testing I had rechanged the front ones to the original with bulbs, no proper result but flashings at the rear.
Then I had installed a load dependant turn indicator relay and deleted the resistors completely and all were fine.
Only pain at the 12 is, that you have to remove in total 19 screws to get the battery slider out, on which end the relay would rest into its socket.
Had used a similar like this. LED Indicator Relay 2 PIN for Kawasaki ZX-12R NINJA ZXT20A/A 2000-2001 | eBay