It is not possible to edit Property:P1477 because labels in fi and cy and perhaps many other languages conflict with Property:P513. Somehow it was possible to add those labels/descriptions at some point, but now the conflicts show up on every attempt to modify the property.

See also here and here.

The fi label was set on 31 March 2015 although on the other property the same label existed since 22 August 2013‎. This is the edit which should not have been able to be done.