Plumber will put icons for Bountiful Delves and Special Assignments on the World Map, it seems by using the BlizzardUI map pins.

When using Plumber in combination with Map Pin Enhanced, on every reload, these will be tracked as map pins. Since MPE allows unlimited map pins, it will save and track all of them.

Toggling the option off and on during a session does not reactivate the map pins.

Is it possible to actually clear the map pins for every delve/assignment marked?

Hi!
Its dev has reached out to me. Updating Plumber to the latest version should fix it.

Fix seems to be working, thank you!

Sorry, I think it's still happening the very first time you get the Special Assignment on your map? But no longer every time you relog/reload.