KMServer adopts databases built by komga-riir (a parallel Rust reimplementation), which record migration history in sqlx’s _sqlx_migrations instead of flyway_schema_history. The Java version cannot open such databases at all.
Adoption stamps the sqlx-recorded versions (and the Java JDBC data-fix ports from an explicit whitelist, which must not run against komga-riir-shaped data) into a rebuilt Flyway history; KMServer always applies its own book_projection. Migrations komga-riir applied beyond a Java komga / KMServer history are also absorbed so their DDL is not re-run.