Network calls intermittently do not occur in Published play mode on a Canvas app

Problem: An app created does not run Patch or any other network call when published and in run mode. The network calls work in edit mode.  Looking at the logs, I identified some users are successfully updating using network calls

Figure 1. Monitoring shows the Edit/Play working and the Publish/Play not making any network calls.

Initial Hypothesis:

The Patch call works in edit mode, and then intermittently, some users get it to work in Published/Play mode.  This tells me the data in the Patch call is causing the network patch call to fail.

Using a Trace and running in play mode, I remove properties until I find the offending property.

Figure 2. In edit mode, a label control, CurrentDateVaue_1.Text is used

Once, we traced the value of CurrentDateValue_1, which is set by the global variable varCurrentDateTime. As this is done on a random screen, if the user does not open the screen in Publish /Play mode, the label control CurrentDateValue_1.Text is never set. 

Resolution: Replace all the code using CurrentDateValue_1.Text with the variable varCurrentDateTime. The label control is not set when the network/patch call is made, and bizarrely, it does not happen. I'd expect it to send regardless and let the error handling catch the issue.