Imagine this scenario:
... few changesets already applied
1. another changeset creates a table
2. subsequent changeset alters that table changing a column's type
If both changesets were not applied yet, liquibase runs as a single transaction causing that behaviour. In my opinion every changeset might be run an isolated transaction.
Windows 10 build 14393.693, JRE8, JDBC 6.0 (sqljdbc42.jar), SQL Server 2016