LED Gremlins

[Origin7]

I am converting the halogen indicator lights on my older Cat to LED. I am wondering if anyone else has encountered the issue I am having. 

 

I did the following:

 

1. Installed LED bulbs in the front indicators

2. Installed an LED relay

3. Installed rear indicator bulbs

 

So far, so good. Everything worked fine and was super bright. Next, I installed factory Caterham LED front side markers. This is when the gremlins arrived. Now, all 6 are blinking together, instead of 3 right or 3 left. Voltage had to be backfeeding between the left and right sides somewhere in the circuit. The two common components are the relay and the dash light. The relay tested fine, so I removed the bulb on the dash. Sure enough, this fixed it. So I need a more permanent solution. My dash indicators are 37 years old. Does anyone know if newer ones will resolve this?

 

Thanks in advance.