There are two settings Step Complete Sound and Quest Complete Sound. We do not have Objective Progression Sound. Objective Progression Sound makes a sound when you pick up the first item of the ten or fifty items, which is what you described, which is defiantly another addon that’s doing that.
    Here’s Dugi Guides quest and step sounds – here
    Here’s a third party addon, for me it’s ProjectAzilroka – here
    You may need to sift through your addons, it’s defiantly another addon that’s responsible for the progression sound.