indices get corrupted if keys are too big

CREATE TABLE IF NOT EXISTS T1 (B TEXT, C TEXT);
CREATE INDEX IF NOT EXISTS T1_idx on T1 (C,B);
INSERT INTO T1 (B, C) VALUES ('A', 'tms_doc_cfg');
INSERT INTO T1 (B, C) VALUES (RANDOMBLOB(17000), 'tms_doc_cfg_element_trans_xslt');
SELECT * FROM T1 WHERE C = "tms_doc_cfg";

returns nothing.

SELECT C,C="tms_doc_cfg" FROM T1 WHERE C > "tms_doc_cfg";

returns 1 in the 2nd column on 'A' .. The index clearly fails..

If the key length is reduced, the select

CREATE TABLE IF NOT EXISTS T1 (B TEXT, C TEXT);
CREATE INDEX IF NOT EXISTS T1_idx on T1 (C,B);
INSERT INTO T1 (B, C) VALUES ('A', 'tms_doc_cfg');
INSERT INTO T1 (B, C) VALUES (RANDOMBLOB(1000), 'tms_doc_cfg_element_trans_xslt');
SELECT * FROM T1 WHERE C = "tms_doc_cfg";

correctly returns 'A', 'tms_doc_cfg'.