This has been happening to me as well (I’m on PS4), specifically the footsteps volume being low for some enemies but loud for others, even in the same position and circumstances. I posted a video about this earlier today and in the general forums a few days ago. The post is here: Audio Priorities Issue/Bug
Here’s my video proof, you can see in a quiet Petra corridor that a McCree walks up and flashbang kills me completely out of nowhere unannounced as though he teleported next to me, but minutes later in the exact same spot I can hear a Widow walking from the same direction down the hall towards me clear as day.
I think there’s a bug in the “Importance System” in the game sound design, it’s incorrectly prioritizing sounds making the greatest threats quieter than they’re supposed to be, so that some are inappropriately quiet and others loud.
My video was uploaded directly from the PS4 to Youtube and I’ve listened on multiple devices (smartphone, laptop, TV surround soundbar, Sennheiser headphones, etc.) and the footstep volume discrepancy is the same: McCree quiet, Widow loud.
I’m hoping a mod can forward this issue to the sound design team, something is broken or causing incorrect behavior.