Why is /fixQuest so broken

I am stuck on a quest because /fixquest doesn't work well. When i use it, it just fills my inventory with qest items that i have already completed, and i cant progress. If the game just ran a simple check to see what quests i have already completed, than this annoying bug would be fixed.
PLEASE FIX THIS AHHHHHHH

 

if you mentioned what quest you were stuck in, and how, people might be able to actually help you

 

Its hard to keep track of all the quests adn what u have done and scanning all ur pages for the item which they dont have tools for and ye, Its just a lot of data and confusion

 

If you put the unneeded stuff in your crafting grid, fill the empty spots in your inventory with emeralds, and then close your inventory, it deletes the items. You can only do this with 4 items at a time but the effort is worth it when you get your bank slots back

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I would assume Fantastic Voyage since that quest is at their level and they have yet to complete it, but I don't think Fantastic Voyage has any quest items in it

 

That command is just for quest items (items with that specific tag), it doesn't "fix" your quest, it a bit outdated (it used to be extremely more useful back in the day) since we are kinda moving away from those items and tend to add failsafes for them in case you lose them.

Make a bug report about what quest you are having issues with, make sure to include as much detail as you can think of so i can take a look at it and possibly fix it.