Baldur's Gate : The Sword Coast Chronicles : NWN2 Persistent World

Can't figure this out, maybe someone can.

Have Aasimar Sorcerer 10 / Dragon Disciple 1 with base charisma of 21 (+5). i notice when polymorphing with charisma +3 item equiped for 24 cha (+7), I lose 1 spell level 1 and one spell level 5 after each polymorph to normal form.
If I remove +3 item, I notice when polymorph that for 1 second the cha go to 23 (+6), then back to 21 once polymorphed, and return to normal form there is no lost spells.
I put back +3 cha item and when polymorph the cha stays at 24 (21 +3) but when return to normal form, lose spell level 1 and spell level 5 each polymorph.
I have no spell bonus items.

If I remove cha +3 item only in norm form, spellbook lose spell level 3 and spell level 4 each time until zero only.

Why does cha +3 item make it lose spells of all different levels from doing different things? Why not with cha +3 item make cha temp go to 26 and save spells?

It's to do with the racial modifiers and the fix in place with it. Cast Eagles splendor on your self and changing shape should have no effect on spell slots.

Strange fix to me. Okay, does +4 cha item also count? Eagle splendor not spell on my sorcerers list, and scrolls would be dispeled.

+4 Item would fix issue same as Eagles splendor? Or must be a spell casting?

TY.