Cracking sound when two different .wav files overlap each other in fMOD

Hey there!

I am trying to make an engine sound for the simulator called Assetto Corsa, however, doesn’t matter which and how many .wav files I use, I keep having this crackling sound between two overlapping .wav files (notice how the yellow line is jumping when the crack can be heard). I thought it would be the fact that the two .wav files sound very different but even if I use the same .wav files next to each other the crack can still be heard.

Is there anything I can do about this? Unfortunately the game’s audio pipeline and the community couldn’t help about it.

Note that the game only supports 1.08.12.
Thanks in advance for your help!