The snippet function is marking incorrect highlight extents in sqlite 3.44.0 Sample sqlite script

CREATE VIRTUAL TABLE fts_table USING fts5(t, tokenize = 'unicode61 remove_diacritics 2');
CREATE VIRTUAL TABLE fts_row USING fts5vocab(fts_table, row);
INSERT INTO fts_table(t) VALUES ('你dont叫mess');
SELECT term,doc FROM fts_row;
SELECT snippet(fts_table, 0, '>', '<', '...', 4) FROM fts_table WHERE fts_table MATCH '叫';

Output with sqlite < 3.44.0

dont|1
mess|1
你|1
叫|1
你dont>叫<mess

Output with sqlite 3.44.0

dont|1
mess|1
你|1
叫|1
你dont>叫mess<

Notice the trailing < is in the wrong position. Note that this script is not sufficient to reproduce on its own as it uses a custom tokenizer (unicode61 here is overriden in a custom sqlite extension). However, the output indicates tokenization is correct in both versions, so the issue must be in the snippet function.

The code of the tokenizer is here: https://github.com/kovidgoyal/calibre/blob/master/src/calibre/db/sqlite_extension.cpp

However its not standalone and depends on ICU and snowball stemmer etc. But since the tokenization is correct it shouldnt matter.

If there is some more information I can provide, please ask.