Removing, changing or putting on a head talisman seems to randomly cause instant death in Jack instance. Also at times putting on some head talisman is just refused entirely, with no message on any chat (that I could find), and other talisman causing no problem.
Maybe the hp drop from gear change combined with the momentary loss of Equal Footing causes the hp to drop below 0, or something?
I don’t know if it’s dependent on which talisman is used, but red Tachyon Pigment (both level 1 and 70) at least caused me instant deaths, blue and red basic Pigment did not.
The Strong Force and Ashes of Fate’s Chosen (red 70) were ones it just refused to wear most of the time.
I did the gear changes out of combat (no combat going on), instant deaths from full health happened both by the portal and close to the Jack’s end of the path.
Other talisman slots seemed to work ok, only head talismans kicking my ■■■.
Edit:
Found out more: (With my gear) this seems to happen only with 77% or more tank AA.
With 76% tank AA I’m still left with 13hp and survive the talisman swap, with more tank AA I die.