I'll have to test, but 15w35e sounds like it might have fixed at least part of it. Testing is required, however.
EDIT: It didn't fix it, not by a long shot. The test, however, did have fewer mobs experience... whatever was going on with them.
Screenshots attached and report updated.
I've noticed this in earlier versions. Exactly how far back, I do not remember, but it exists in the 15w34 snapshots. It also seems to function with sounds that play when you break a block, as well as when you place one. It likely works with most sounds.
Added steps.