Solved ETK I-Series exhaust instability with custom engines

So, basically, something weird is going on with the exhaust's .jbeam when Installing any previously made custom engines. The exhaust literally ejects itself out of the car, then spins. I haven't figured it out yet.

 

I've even tried to re-write the nodes, beams and triangles, but it doesn't work.

 

So that's why the console said "duplicated beams".
Thank you.