I was unable to reproduce this issue on our end with the information provided. After reading over the logs I noticed that you are receiving the error " Aynı anahtara sahip öğe zaten eklenmiş. (item with the same key has already been added.)" I have provided a link to a user with a similar issue. You will notice that there are a few links to separate solutions for this error message. Could you take a look at these threads and let me know if any of them help?
Link: Package Error 4.12.5 - World Creation - Epic Developer Community Forums