Index: /trunk/src/org/openstreetmap/josm/tools/bugreport/BugReport.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/bugreport/BugReport.java	(revision 19245)
+++ /trunk/src/org/openstreetmap/josm/tools/bugreport/BugReport.java	(revision 19246)
@@ -160,4 +160,13 @@
         if (isIncludeData()) {
             exception.printReportDataTo(out);
+            // Exceptions thrown in threads *may* be automatically wrapped by the thread handler (ForkJoinPool, etc.)
+            // We want to keep the data saved in the child exceptions, so we print that as well.
+            Throwable cause = exception.getCause();
+            while (cause != null) {
+                if (cause instanceof ReportedException) {
+                    ((ReportedException) cause).printReportDataTo(out);
+                }
+                cause = cause.getCause();
+            }
         }
         exception.printReportStackTo(out);