Preparing a Purging Trap turns your character into antimagic

[LordSputnik]

I do not know if this was intentional or not, but my character is not antimagic and cannot enter Zigur town, and I learned how to make a purging trap by disarming one. Whenever I prepare one, the game treats me as an antimagic and I can't use any arcane gear or certain abilities while it is primed. Was this intentional by design since normally you can only learn it from borrowing Zigur's help during the Storming the City quest line.