Sigils disappearing after death

[Narelle]

It is confirmed that it is intended for a % of your sigils to be destroyed upon death.

Isle of Siptah Sigil Losing Bug

Hey there, On death, you lose a percentage of sigils permanently and they need to be reacquired by going to their vaults. Each Sigil gives you some significant combat advantages to a specific enemy type that spawns within the Maelstrom.