"mvn clean install" builds without problem but "mvn release:prepare" fails with compilation error

Platform: debian 12.11 "bookworm", amd64
          java 21.0.4 2024-07-16 LTS
          Apache Maven 3.8.7

I have a Java project built with maven that builds ok with "mvn clean install"
 https://gist.github.com/steinarb/389a0b9c3e33cd186536bc476c0d9e1d
but fails with "mvn release:prepare"
 https://gist.github.com/steinarb/b4245e26cd10ee3a3def70e16438ba40#file-gistfile1-txt-L647

The failure in "mvn release:prepare" is a compilation error in
testCompile, and the symbol that can't be found is a class in the same
package as the test in src/main/java:
...
[INFO] [INFO] --- maven-compiler-plugin:3.14.0:testCompile (default-testCompile) @ authservice.db.liquibase ---
[INFO] [INFO] Recompiling the module because of changed dependency.
[INFO] [INFO] Compiling 1 source file with javac [debug release 21] to target/test-classes
[INFO] [INFO] -------------------------------------------------------------
[INFO] [ERROR] COMPILATION ERROR : 
[INFO] [INFO] -------------------------------------------------------------
[INFO] [ERROR] /home/sb/workspaces/authservice/authservice/authservice.db.liquibase/src/test/java/no/priv/bang/authservice/db/liquibase/AuthserviceLiquibaseTest.java:[56,40] cannot find symbol
[INFO]   symbol:   class AuthserviceLiquibase
[INFO]   location: class no.priv.bang.authservice.db.liquibase.AuthserviceLiquibaseTest
[INFO] [ERROR] /home/sb/workspaces/authservice/authservice/authservice.db.liquibase/src/test/java/no/priv/bang/authservice/db/liquibase/AuthserviceLiquibaseTest.java:[137,40] cannot find symbol
[INFO]   symbol:   class AuthserviceLiquibase
[INFO]   location: class no.priv.bang.authservice.db.liquibase.AuthserviceLiquibaseTest
[INFO] [ERROR] /home/sb/workspaces/authservice/authservice/authservice.db.liquibase/src/test/java/no/priv/bang/authservice/db/liquibase/AuthserviceLiquibaseTest.java:[159,40] cannot find symbol
[INFO]   symbol:   class AuthserviceLiquibase
[INFO]   location: class no.priv.bang.authservice.db.liquibase.AuthserviceLiquibaseTest
[INFO] [INFO] 3 errors 

All ideas and hints are welcome! Thanks!

(I presume this is a problem to do with this being built with a
non-snapshot version...? I see 3.0.2 in the failing compilation and that
is the version I am trying to release?)