A pickup / interact with world quest can easiely been overlooked when there are other objectives in the same area.

Example: https://ibb.co/z7j0p71

In this case the "Furlbrow's Pocket Watch" from https://classic.wowhead.com/quest=64/the-forgotten-heirloom should use a different and outstanding marker to make it more present.

This is definitely a problem I agree. Actually, we've been discussing giving "loot from a container" like the pocket watch have a different icon that is slightly larger, so it stands out a lot more visually

Also, once the tracker is implemented it will be easy to only show notes from quests you want to see, so that should help too

There are options to colorize the icons differently which helps on this issue and you can also focus a quest to fade out icons which don't belong to the focused quest.

Report back if this doesn't solve the issue.