This is incredibly cool, finding almost 200 bugs in SQLite is a really great achievement. I'd certainly be interested in how often these bugs come up in real applications.
When the user reported the bug, it had actually already been fixed on the latest SQLite3 trunk based on one of our bug reports. The query in our test case used a “NOT NULL NOT NULL” predicate, which is unnecessary complex as well: https://www.sqlite.org/src/tktview?name=c31034044b. We believe that this is interesting evidence that even “obscure” bugs matter in practice, for example, when the queries are automatically generated, as demonstrated above.