Hello there,
in the item Q870 (http://www.wikidata.org/wiki/Q870) it's not possible to remove the property "is instance". I always get this error message:

• A length constraint is triggered for language code "ru". * There is {{PLURAL:1|a constraint|constraints}} violation for {{PLURAL:1|description|descriptions}} "сформированный ..." for {{PLURAL:1|language code|language codes}} "ru".

Best regards,
#Reaper

Version: unspecified
Severity: critical
URL: http://www.wikidata.org/wiki/Q870