Resolved:
Trusts are to be called inside the BC. I was trying to call the ones I had call outside again inside, which were in cooldown and therefore couldn't be called again.
Keeping for history:
Platform:
Windows
ISP:
1&1
Type of Internet Connection:
DSL
Internet Connection Speed:
50Mbit/s
Date & Time:
22:00 GMT+2
Frequency:
Always
Character Name:
Ilisidi
Race:
Mithra
World:
Odin
Main Job:
WHM95
Support Job:
BLM
Area and Coordinates:
All fight areas for Limit Break Quest Beyond Infinity
Party or Solo:
Solo
NPC Name:
Burning Circle
Steps:
First attempt was WHM94, had Nomad Moogle send me to one of the available zones (Qu'Bia Arena), called five trusts, interacted with Burning Circle, all trusts disappeared after choosing Beyond Infinity when the cutscene started.
Second attempt was at Waughroon Shrine, same behaviour as above.
Third through fifth attempt was WHM95, same steps as above, tried a different battlefield each time and varied trusts. End result was the same, trusts disappeared as soon as the cutscene after choosing Beyond Infinity started.
This bug has been reported as a Known Issue in one of the update notes from 2014. If it can't be fixed I'd like to know how I can avoid it. I have no intend of going through the hassle of shouting for a party.