I was checking the "Automated Collapse/Expand" option and performing the quests.
If you check this option, you must have certain conditions, such as expanding the list of quests in your region and folding the list of non-regional quests, but the completed quests were bound to fold.

The "Iverron's Antidote" quest that I'm doing is a time-limited quest, marked as a completed quest like a screen shot and folded the list, so I almost couldn't do it.
I was able to complete most of the quests without making a mistake, but this function allowed me to miss the time limit quests.
If it is simply a function to hide completed quests, you should show the correct orientation of this feature with the options already in the AQT.
You'll also need to refine the name of this option.

Could be that it interacts oddly with zone-based autotracking enabled. I'll take a closer look at things, and see if I can clarify things some more as well.

And I should consider adding an option to always show timed quests.

Related to this: as of the most recent commits (not sure if it currently applies to any release versions), timers will not show up once quest is started. Only updating the config options will make the timer display.

And since I need to remind myself that I should not go complete the timed quest, because I need it in order to try potential fixes, I should probably consider eating. Because apparently my brain can't even function on the most basic level right now.

This is working after the patch.
However, it is still not functioning normally outside before entering the instance.
I found it folded when I was soloing to perform Maraudon's external quest.

And one more thing, I'll tell you what.
The "Favored of Elune?" quest has header as Rut'theran Village to accept in Rut'theran Village
In fact, the area to carry out the quest is Hinterlands.
I wonder if these quests will function normally in this function.

@chkmyid Some of the quests do show that way, but the default wow UI assigns to areas the same way in the quest log. There are quite a few quests located in Orgrimmar for instance that send you to Ungoro, but the UI assigns them to Org still. So I think the second portion of the comment here would require an audit of quests in wow, and manually assigning headers to them. I have an easier solution that I'm proposing soon though, that can hopefully be implemented.

There is one workaround in the current code: if you manually expand a header, it will stay expanded, regardless of automation rules.

I will be looking at manually moving quests to a different header.

Also yes, I only work on information supplied by the API. So if a quest shows up under a header in the questlog, that's the header it will go under. Anything else would require a maintained database of quests.

The solution I propose is to scan the description of the quest and create a "associated quest" header if a name matches that zone and display it under the header of that zone.

However, for the "the star, the hand and the heart" quest, you must visit three zones. The names of the zones to perform the quest are listed in "bonegrip's note". It may not be appropriate to scan the quest description and make it visible if it matches the zone name.

Moving the three zones of the quest by manually moving the headers will increase the click count, which may eventually lead to inconvenience.

That's an interesting idea. However, the current architecture does not support having multiple uiobjects for any header/quest/objective object. It shouldn't be too much work do modify this property, however, it needs to be done with caution, as it's on a level that risks a fairly high amount of breakage.

Second, I will need to do some research on how to, assuming if, the API will allow me to build a list of the zones, as that is far preferable to a pre-supplied one (future compatible with no need for maintenance). Then it would be a fairly simple matter checking the list against the quest description. It could, of course, lead to false positives.

If part of the quest takes place in a zone not mentioned in the description, it would require special handling, and maintaining a database with quest information within the addon. Something I am not overly keen on doing at the moment, as it is a bit too close to quest helper territory.

One option I would be more likely to consider is using a quest helper addon as an optional dependency, and if there is one that has an api to supply other addons with information on the zones a quest takes place in, grab the information from it.

On the whole, it would take a relatively high amount of development time, but I will consider my options over the next few days, and look into a few of the things mentioned in the post.