Same issue.
Server: Telsiai
Team Name: M0rDred
Character Name: Avacyn (Lv 257 Templar Rank 7)
Details: I equipped 6 cards including some rare ones (Tomb Lord and Nuaele) while I was in Ferdimian by dragging the cards to the card slots starting with the rightmost slot. I then wanted to check if my cards would gain exp from monster kills and so, I teleported to Sventimas Exile via the Goddess Statue for that purpose. Once there, I checked my card slots only to discover in horror that they were gone (or invisible, I couldn’t tell since my cards specialized on bosses). Right clicking on the occupied slots doesn’t do anything.
Please set the fix for this bug as your top priority! You may also want to perform internal testing for future patches before releasing them. I don’t really mind delays in releases as long as they are fully tested and optimized.