PATCH w/ SPARQL Update fails on boolean values

[dan-f]

First request to PATCH /solid-bookmarks/bookmarks.ttl (HTTP 200):

INSERT DATA { <https://dan-f.databox.me/solid-bookmarks/bookmarks.ttl#6bfcbd11-b760-45d8-a184-0403c1d1a14a> <http://www.w3.org/ns/solid/terms#read> "1"^^<http://www.w3.org/2001/XMLSchema#boolean>  };

Subsequent request to PATCH /solid-bookmarks/bookmarks.ttl (HTTP 409):

DELETE DATA { <https://dan-f.databox.me/solid-bookmarks/bookmarks.ttl#6bfcbd11-b760-45d8-a184-0403c1d1a14a> <http://www.w3.org/ns/solid/terms#read> "1"^^<http://www.w3.org/2001/XMLSchema#boolean>  };
INSERT DATA { <https://dan-f.databox.me/solid-bookmarks/bookmarks.ttl#6bfcbd11-b760-45d8-a184-0403c1d1a14a> <http://www.w3.org/ns/solid/terms#read> "0"^^<http://www.w3.org/2001/XMLSchema#boolean>  };