Attempt to change information for the account/user or send notification for the account/user fails with an exception
Field should contain latin characters only. Please correct.
The issue is caused by the presence of the language code like 'en_US' in the BA. Since BA 6.0 such language codes are not allowed, but they were accepted in 5.5, moreover they are still accepted by APIs, which us a bug with id #PBA-72762 ("Field should contain latin characters only error after BA upgrade").
To find and correct all the affected records please contact Odin Technical Support Team.
Do not use this language code in APIs to avoid an issue.