Using the merchant with doublevariant equipment chrashes theserver

I use two armor sets to play with. The set items for helmet, chest, leggins and boots are the same, only different in item level and effects.
All other stuff like weapons, artifacts and talisman are the same on both sets.

The bug comes from my equipment by using double variant effect.
I have that effect on all items with an overall 75% chance.

When i use the merchant, the item change won’t work and if i leave the merchant, all npc’s are standing still. After one minute i loose the connection to the dedicated server with error code: 0015

I tried using some other armor items and every time by using items with double variant effect the merchant is unusable and if i do not reconnect, i will loos the connection as i said above.