Orbis PQ impossible to complete

Description of the bug: When doing OPQ in channel 1, at the very end of the PQ where you drop the grass of life on the statue of the goddess to summon Minerva and complete the PQ, Minerva does not appear, rendering the PQ impossible to complete. In channels 2 through 6, no party members aside from the leader are able to enter the rooms in the tower making it impossible to progress any further after stage 1.
What is supposed to happen?: Dropping the grass of life on the statue in the middle of the tower is supposed spawn the NPC "Minerva the Goddess," who then awards the party with exp and sends them to the bonus stage. After the leader enters any room in the tower, all other party members should be able to enter.
Where did you find and/or notice this bug?: Orbis Party Quest, Tower of the Goddess.
A step-by-step guide to re-producing this bug (optional): Play through Orbis PQ to the end in channel, play through Orbis PQ up to the 2nd stage in channels 2-6.
Extra information (optional): I was able to do about 7 successful runs of OPQ before this bug started to occur, not sure what changed to cause this after the 7th. GM David assisted my party in finishing the PQ by manually spawning Minerva but the issue continued on subsequent attempts and he had to help us out multiple times. He suggested changing channels but that only lead us to discover that every other channel was more bugged.

 

This all happened in the same day. The successful pqs were directly before the bugged ones.

 

It did happen again, however we eventually found a way to consistently prevent it from happening. By not playing in ch1 (not sure if this actually mattered, but we did it anyway), reforming the party, and changing the leader after every pq, we were able to stop it from happening altogether.