Getting StreamCorruptedException in debug mode

Hello,
In a flow service, a Java service gets invoked which is using propritery APIs of some back-end system.
When I run this flow service using Designer/Developer/IS-Browser it runs fine, but if i debug it then Designer/Developer throws below exception:

java.io.StreamCorruptedException: invalid type code: 0B
at com.wm.util.coder.IDataBinCoder.doJavaSerializationDecode(IDataBinCoder.java:1221)
at com.wm.util.coder.IDataBinCoder._decode(IDataBinCoder.java:1185)
at com.wm.util.coder.IDataBinCoder._decode(IDataBinCoder.java:818)
at com.wm.util.coder.IDataBinCoder._decode(IDataBinCoder.java:818)
at com.wm.util.coder.IDataBinCoder._decode(IDataBinCoder.java:818)
at com.wm.util.coder.IDataBinCoder.decode(IDataBinCoder.java:307)
at com.wm.driver.comm.b2b.http.SessionHTTPLink.transportMsg(SessionHTTPLink.java:103)

My suspiction is that the output of the Java service (A java object) couldn’t be deserialized by the tool(Designer/Developer) and hence throwing exception.
Any pointers to resolve/better understand the issue could be of great help.
Thanks in advance.

Regards,
Manoj