https://l2wiki.com/Red_Thread_of_FateBug start when you use "Fondest Heart" on "The Deserted Dwarven House"
The quest item will disappeared but you can't continue the quest.
You can fix these by changing the
<reuseDelay>10000</reuseDelay> to
<reuseDelay>1</reuseDelay>
of skills 9579-Clearest Water
9580-Brightest Light
9581-Purest Soul
9582-Fiercest Flame
9583-Fondest Heart
game\data\stats\skills\09500-09699.xml