v8.8.1 - Classic Era
In previous versions there used to be an option for the tracker to show the completed quests in "compressed" mode, i.e. a completed quests were shown as "xxxxxxx (Completed)" in one line.
Can't see that option any more and now every completed quest shows with an extra line with a green "Quest Complete!" text.

Tracker option, check "auto minimize completed quests"

I thought it was that, but that option doesn't do anything at all. Tried disabling/enabling/reloading, but nothing changed.
Don't know if it conflicts with one of the other settings.

Try and uncheck "Auto Minimize Completed Quests" then check "Hide Blizzard Completion Text" then RECHECK "Auto Minimize Completed Quests" then report back.

Some options, like "Hide Blizzard Completion Text" are disabled like you can see in my screenshot.
I don't know what controls that option, but it seems permanently disabled (grayed out), so I can't change it.
Tried flipping all the other options, but it stays disabled.

Oh right... wrong option. Your Objective Color profile is set to "Minimal". Set it to something else... then check "Hide Blizzard Completion Text" THEN set the color profile back to "Minimal".

Hmmm... must have some of the flags set wrong. I'll look into it.

Tried again, but the extra "Quest Complete!" line is not going away, no matter the combination of "Hide Blizzard Completion Text" and "Auto Minimize Completed Quests".

i tried to match their settings? seems to work fine on my end..

I think he has the quests without objectives. Those are special, i'm not sure if the fix is on live or not.
When i tested the fix, it was working, minimizing quests w/o objectives, but now it's stuck on showing "quest complete" for those, for me too on Wotlk

er.. d'oh!