Sekhema's Cloak Major Boon does not function

The Sekhema's Cloak boon in the Trial of the Sekhemas reads:

"

Upon reaching 0 Honour, revive once with full Honour

Today I was helping a friend with one of his ascension trials and we went into the Zarokh fight with his honour being low, but was not worried as we had the Sekhema's Cloak boon. However, once his honour reached 0, his character immediately was incapacitated without being revived or any Honour restored. He was full on life and did not die through combat.

Details of any possible relevance:
* I was the instance owner who started the trial, the player for whom the revive failed to trigger was not
* Level 77 Djinn Barya
* We had a single affliction reducing max honour and a single boon increasing max honour, we had no other boons or afflictions affecting honour restored
* We did not have any afflictions that would prevent honour being restored such as Branded Balbalakh or Haemorrhage