Running tests again emits "The test commands failed to create AppMaps"

I executed the agent commands in https://github.com/spring-projects/spring-petclinic to record tests.

On the 1st run, it correctly printed that 40 AppMap files were created.
On the 2nd run (without code changes), it printed an error that no tests were recorded.
IMHO this shouldn't happen because the mvn test command was successfully executed and most likely only updated the existing .appmap.json files with new timestamps.

[WARNING] Tests run: 41, Failures: 0, Errors: 0, Skipped: 1
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  34.165 s
[INFO] Finished at: 2022-09-05T11:49:16+02:00
[INFO] ------------------------------------------------------------------------

! The test commands failed to create AppMaps

Help is available from the AppMap support team! If you want assistance, the test command,
error message, exit code, and APPMAP environment variables can be uploaded securely to the
AppMap ZenDesk support portal. The AppMap team will respond to you by email, so we'll need your
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Reproduce the report in spring-projects/spring-petclinic by running the AppMap agent commands with mvn test twice without changing code. Start at the code path that emits "The test commands failed to create AppMaps" and trace how existing .appmap.json files are handled. Done means a successful second test run no longer reports that no tests were recorded, with regression coverage for the repeated run.