Stuck in Lost Temple 0.9 - Can't retrieve missing pieces

I am stuck with 2 Characters at the lost temple quest where I can’t retrieve any of the missing parts. It’s not showing me any quest tracker on the map nor letting me interact with the crystals.

Probable Bug origin:
Both characters have been in a party with a character who has already completed the questline at the time of partying (~lvl 30 hanging out in the lost refuge).
Nothing changed though at the moment of partying for the characters and all other quests could be completed with no issues later on. (I just wanted to have some waypoints ready for a quicker 2. and 3. playthrough) I had found it already weird that the quest of searching the temple didn’t progress when taking the waypoint straight through the temple, hence I had to do the walk anyway, which eventually got the quest to progress up until the now stuck point.