Ambient sound lowers when sfx plays

When an SFX sound plays the ambient sound ( which i am using for the background music) lowers automatically for some reason, is this intended? is there anyway to disable this?

I am using 4.7, but this doesn’t look like a bug but an intended feature so i guess that is irrelevant…

Some help would be greatly appreciated as this seems like a simple issue that i just can’t figure out.

Make sure the sound isn’t playing with a sound class that has a passive sound mix modifier enabled.

I tried changing the background music’s sound class to “music” and the sfx classes to “SFX” and nothing, any more tips?