btrace with glassfish web container

Recently I use btrace to check exceptions that are thrown inside glassfish 4.1 b13 VM. When I attach to GF 4.1.1 (build 1) with BTrace v.1.3.10.2 (20180129) using '-v' the following stracktrace is generated by GF and I see no console output thrown by btrace:

btrace DEBUG: parsed command line arguments]]  
btrace DEBUG: Bootstrap ClassPath: .]]
btrace DEBUG: ignoring boot classpath element '.' - only jar files allowed]]
btrace DEBUG: System ClassPath: /usr/lib/jvm/java-8-oracle/jre/../lib/tools.jar]]
btrace DEBUG: debugMode is true]]
btrace DEBUG: probe descriptor path is .]]
btrace DEBUG: stdout is false]]
btrace DEBUG: starting agent thread]]
btrace DEBUG: Agent init took: 10482105ns]]
btrace DEBUG: starting server at 2020]]
btrace DEBUG: waiting for clients]]
btrace DEBUG: client accepted    Socket[addr=/127.0.0.1,port=43496,localport=2020]]]
btrace DEBUG: got instrument command]]
btrace DEBUG: loading BTrace class]]
btrace DEBUG: verifying BTrace class ...]]
btrace DEBUG: BTrace class com.sun.btrace.samples.OracleNsPacket  verified]]
btrace DEBUG: preprocessing BTrace class com.sun.btrace.samples.OracleNsPacket ...]]
btrace DEBUG: ... preprocessed]]  
btrace DEBUG: loaded 'com.sun.btrace.samples.OracleNsPacket' successfully]]
btrace DEBUG: creating BTraceRuntime instance for com.sun.btrace.samples.OracleNsPacket]]
btrace DEBUG: created BTraceRuntime instance for com.sun.btrace.samples.OracleNsPacket]]
btrace DEBUG: sending Okay command]]
btrace DEBUG: client com.sun.btrace.samples.OracleNsPacket: got com.sun.btrace.comm.OkayCommand@26cab401]]
btrace DEBUG: about to defineClass com/sun/btrace/samples/OracleNsPacket]]
btrace DEBUG: defineClass succeeded for com.sun.btrace.samples.OracleNsPacket]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/agent/RemoteClient$1]]
btrace DEBUG: starting client command handler thread]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/agent/Main$3]]
btrace DEBUG: new Client created com.sun.btrace.agent.RemoteClient@44c6c5b2]]
btrace DEBUG: retransforming loaded classes]]
btrace DEBUG: filtering loaded classes]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/runtime/ClassCache$Singleton]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/runtime/ClassInfo$ClassName]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/runtime/ClassInfo$JavaClassName]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/runtime/ClassInfo$BaseClassName]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/runtime/ClassInfo$InternalClassName]]
btrace DEBUG: skipping transform for BTrace class com/sun/btrace/runtime/BTraceClassReader$BailoutExceptio]]
btrace DEBUG: java.util.concurrent.ExecutionException: java.lang.IllegalStateException: This web container has not yet been started]]

java.util.concurrent.ExecutionException: java.lang.IllegalStateException:    This web container has not yet been started
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:192)
at com.sun.btrace.agent.Main.startServer(Main.java:674)
at com.sun.btrace.agent.Main.access$000(Main.java:60)
at com.sun.btrace.agent.Main$2.run(Main.java:125)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: This web container has not yet been started
at org.glassfish.web.loader.WebappClassLoader.findResourceInternal(WebappClassLoader.java:2827)
at org.glassfish.web.loader.WebappClassLoader.findResource(WebappClassLoader.java:1320)
at org.glassfish.web.loader.WebappClassLoader.getResourceAsStream(WebappClassLoader.java:1528)
at com.sun.btrace.runtime.ClassInfo.loadExternalClass(ClassInfo.java:262)
at com.sun.btrace.runtime.ClassInfo.<init>(ClassInfo.java:215)
at com.sun.btrace.runtime.ClassCache.get(ClassCache.java:70)
at com.sun.btrace.runtime.ClassCache.get(ClassCache.java:62)
at com.sun.btrace.runtime.ClassCache.get(ClassCache.java:51)
at com.sun.btrace.agent.Client.retransformLoaded(Client.java:451)
at com.sun.btrace.agent.Main$3.run(Main.java:693)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

btrace DEBUG: waiting for clients]]
btrace DEBUG: skipping transform for BTrace class sun/security/ssl/ServerNameExtension]]
btrace DEBUG: skipping transform for BTrace class sun/security/ssl/UnknownExtension]]  
btrace DEBUG: skipping transform for BTrace class sun/security/provider/PolicyFile$6]]

The thing I am confused about is the glassfish exception. When btrace is being attached there is already an application deployed on GF that serves HTTP requests. If there is a webapp deployed that uses web container why 'the container has not been started' is raised?

But sometimes it works and btrace output appears..but it is 1/10 tries. Any suggestions what causes this Ex?