2016 Tail Lights Not Working With Engine On

Hi everyone, hope i am posting in the right section :$
I am a happy owner of 2015 V6 and imported my US specs baby to Europe. In order to homologate the car, some modifications were made to the lighting in order to take all kinds of tests on a racetrack. After these tests were done, the car was supposed to be back to original settings. Now i am having a weird issue with the right turn tail light. If engine is off the light works normal as sequential lighting but if engine is running only 1 Led is working out of the 3 hence no tail effect i got the people who made the modifications check the car but from the electric side everything is in place (connectors, wires etc..). Any clue what this could be? Thanks a lot for the help, take care and regards from the Old Continent!!