I encountered this issue after I enabled the “Generate slug from” option.
I mainly use the Japanese language, so the option is useless when I write titles in Japanese. I left this option enabled because I sometimes use English.
However, if I duplicate entries with Japanese titles, every slug is changed to just “1” even though the “Unique filed” option is enabled. This is because slug generation only detects numbers after the title.
You can also reproduce this issue with Korean or Chinese.
I know we can’t use non-Latin languages for slugs. Any advice for better slug generation with CJK languages?
(sorry for bad English)