libthrift is deployed with a "pom" packaging on maven central, see https://repo1.maven.org/maven2/org/apache/thrift/libthrift/0.9.3/libthrift-0.9.3.pom
This is very wrong. "pom" means "no jar, just a list of dependencies to be pulled transitively".
As a consequence, some build tools, such as sbt, don't pull the libthrift jar itself.
The pom should be be using a "jar" packaging, or even no packaging at all as "jar" is the default value.