SQLAlchemy produces valid code for SQLite but not for MySQL

I am migrating a project from SQLite to MySQL. There's no schema error, etc. However, in one case with nested union of subqueries, SQLAlchemy failed to generate syntactically (error 1064) correct MySQL code (it worked when I was using SQLite). This question is not so much about the problem I am having as to has SQLAlchemy been known to fail at such occasion - i.e. successfully generating queries for one engine while failing for another?