LED lights flicker not supposed to

I have a 5 Ton military truck that runs on a 24v system. It is a search and rescue truck for my department. I am installing emergency lighting, spot and flood lights, all LED. I currently have two spot/flood combo lights and an led lightbar on the front bumper. I have blue led emergency lighting all around the truck and two flood lights on telescoping poles. All LED lights are 12v and are run using a 24v-12v converter. All lights are grounded to the truck chassis. I am having an issue with the flood lights flickering slightly when the emergency lights are turned on. I am thinking it is maybe due to all lights having a common ground. Could this be the case? If so, how can I correct the issue or perhaps isolate the grounds to the LED flood lights to eliminate the flicker?

What is the total amps of all lights combined? The gauge of wire used to feed the 24-12 converter? Rated amperage of the converter?

Converter is 750 watts. Total amp draw for all leds combined is approximately 22 amps, and that is a high estimate. I used 8ga wire to feed the converter and the wire length from batteries to converter is less than 2 feet.

Try adding a additional ground from converter to chassis. The 750 watt inverter is it Peak rated? What is the continuous rating if listed if not what is the efficiency % of the converter? I'm wondering if it isn't big enough to handle the full load. IF say it's 80% efficient that's 25 amps peak @ 24v input. You need to know what the continuous out put rating is and use a inverter that is big enough to stay below it. Depending on design Continuous is usually somewhere between 50% - 75% of peak.