Thanks @dkayiwa and @ssmusoke. The issue was on the definition of the HTTP post. I needed to do this within the for loop. Please see the final work at https://github.com/palladiumkenya/openmrs-module-kenyaemrorderentry/blob/dev/api/src/main/java/org/openmrs/module/kenyaemrorderentry/task/PushLabRequestsTask.java
Thanks for the piece of advice. I will incorporate that in the work.
@aojwang you could also try to identifier the offending line by sprinkling around various marked System.out.println statements.