sun/net/www/http/KeepAliveCache/B5045306.java: java.lang.RuntimeException: Failed: Initial Keep Alive Connection is not being reused

The sun/net/www/http/KeepAliveCache/B5045306.java test was observed failing once with:
java.lang.RuntimeException: Failed: Initial Keep Alive Connection is not being reused.

---------System.out:(4/129)----------
http server listen on: 43449
First connection on client port = 35618
Second connection on client port = 35624
server sleeping...
----------System.err:(12/765)----------
java.lang.RuntimeException: Failed: Initial Keep Alive Connection is not being reused
at B5045306.clientHttpCalls(B5045306.java:112)
at B5045306.main(B5045306.java:70)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:125)
at java.base/java.lang.Thread.run(Thread.java:1623)