I searched for this but found nothing.

Using the Creation Kit, I changed the following entries:

FSTArmorHeavy/LightFootstepSet
NPCHorseFootSprint/Run/Walk/Front/Back

When using this plug-in, my quicksave and screen shots make horse hooves sounds. I then made a separate mod, changing only the first two entries (ArmourHeavy/Light), and my quick save and screen shots now make the sound of armoured boots.

How do I fix this?

Thank you

I found a workaround using the same bug-logic. I made an esp modifying the ui_activatefail entry (I added two silent .wav files), and ensured it loaded last in the load order. Now there is no sound associated with quick save or screen shots. However, the bug still exists. From what I have noticed, things which did not have a default sound associated with them (and have no apparent Creation Kit specific entry for sound) were effected by sound modifications. I -assume- this is a bug with the Creation Kit.