The option to clear out the APP_DATA of the translation configuration is still an option. This will clear out all translation configurations in the
SDL Web 8.5 system and the setup must be re-applied. Or you can apply it to the affected publications(s) as per the article:
In SDL Web 8.5, Translation Configuration is not loading for one publication onlyThere is a hotfix as well that allows the API to let you correct a publication(s) configuration for the translation setup:
TM_8.5.0.11520. This fix is available via FTP as per:
Where can I find hotfixes for SDL Tridion/Web?