So I was doing some test of my own and I happened to wear a certain item that grants the shield spell. I already had shield from before so nothing happened first.
Code:
 oOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOo
 o [Affects] Golg 'oroth - Wrath of the Serpent                              o
 o===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===o
 o Affect: 'detect hidden'                                                   o
 o Affect: 'detect invis'                                                    o
 o Affect: 'shield' - deflection bonus to magical protection                 o
 o Affect: 'armor'                                                           o
 o Affect: 'protection'                                                      o
 o Affect: 'infravision'                                                     o
 o Affect: 'spirit aura'                                                     o
 o Affect: 'bless' - morale bonus to probability to hit                      o
 o Affect: 'bless' - morale bonus to willpower                               o
 oOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOo
Then...
Code:
>
wear XXX
It is a bit small for you.
You stop using a turban of shrouding mist.
You shiver as frigid air seeps from XXX.
The frost forms around you.
You are already protected by a force shield.  <-- Yes, I know, thank you.
You wear XXX on your head.
[HP:100%] [ME: 92%] [PE:100%]
I do my tests, I do a remove...
Code:
wear tur
You stop using XXX.
The chattering of your teeth subsides.
Your force shield shimmers then fades away.   <-- WHY?!?
The mystical armor shimmers slightly, and several spirits escape it to surround you in their protection.
You wear a turban of shrouding mist on your head.
[HP: 99%] [ME: 42%] [PE:100%]
And then...
Code:
oOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOo
 o [Affects] Golg 'oroth - Wrath of the Serpent                              o
 o===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===o
 o Affect: 'protection'                                                      o
 o Affect: 'armor'                                                           o
 o Affect: 'detect hidden'                                                   o
 o Affect: 'detect invis'                                                    o
 o Affect: 'infravision'                                                     o
 o Affect: 'spirit aura'                                                     o
 o Affect: 'bless' - morale bonus to probability to hit                      o
 o Affect: 'bless' - morale bonus to willpower                               o
 oOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOo
On remove of XXX my shield was gone, the spell from the NPC that was keeping it on me was released(NPC was back at 100% ME).
Perhaps fix it so it doesn't remove scripted spell unless the item itself casts the spell on the PC and he doesn't have it from earlier.