Hey there,
I've reported this bug 3 times by now. One time in 2012, one time in 2013 and now this time.
http://www.youtube.com/watch?v=mJ0bavEhlzI
Curse glitches out when you switch to a loadout that has no weapons equipped on it. After curse wears off the weapons that were cursed are unequippable. Choosing the loadout with the cursed weapon on it will give an error: "An unexpected error has occured on the server". Viewing the weapons directly in your arsenal shows only the "Compare" option in it though there is no "Equip" option.
I'm just letting you guys know, once again, about this bug.
This doesn't seem serious, and it is a replicable but avoidable glitch.