Play Scala integration tests are flaky

[PerfectSlayer]

Test suite

user blocking from PlayScalaRoutesServerTest
Marked flaky by [APM Java] dd-trace-java continuous integration dashboard.

Error

Condition not satisfied:

response.code() == USER_BLOCK.status
|        |      |             |
|        500    false         403
Response{protocol=http/1.1, code=500, message=Internal Server Error, url=http://localhost:38739/user-block}

	at datadog.trace.agent.test.base.HttpServerTest.user blocking(HttpServerTest.groovy:1745)

Cause

Note sure of the root cause. Maybe client get some other response from error route tests?

Environment

It looks Java 8 mostly: ibm8, semeru8, oracle8.

Logs

test.zip