Probably some bug fixing. I haven’t seen this for me, but with the issues that Europe West is having, I would assume it’s just maintenance or some sort of bug fixation.
Hello welcome to our forums! 
We apologize this issue is affecting you !
Could you please try the following steps to check is not a visual bug.
- Close Lost Ark completely
- Force Stops Steam
- Run Steam as administrator
- Verify game files on steam
- Open Lost Ark
Thank you for your patience.
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