Defensive spells being dispelled upon equipping stuff

[Winthorp]

Let's say I cast a Stoneskin or a Ghostly Visage etc on myself. Then I equip a sword. The Stoneskin, etc, gets dispelled. Same if for example I am wearing "city" clothes and cast one of those spells on myself, then equip a proper armor: the spells get dispelled. I checked on the "Dismiss Spell" menu and they are definitely being dispelled, it's not a visual issue. This happens with several spells (as I said, Stoneskin, Ghostly Visage, but also Keen Edge and others).

Any idea?

edit
this has been going on through several server resets btw

[Valefort]

Are you equipping the item while casting the spell ?

[Winthorp]

No

edit
if you're online now I can show you