Causes for "JSON.parse: unexpected character at line 1 column 1 of the JSON data"

If I look this in Stackoverflow, it is regular to get this if you try to parse an empty string (https://stackoverflow.com/questions/25743994/syntaxerror-json-parse-unexpected-character-at-line-1-column-1-of-the-json-dat)

When I open the browser console, here is the message:

Dispatch of asynchronous action failed: SynthaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

    actionCountingPromiseMiddleware

You will need to add the JSON here for us to take a look at. With the description you have provided, it looks like the JSON varies based on user context and some of them might be receiving an invalid JSON. 

I suggest to open a support case as this is nothing you can influence directly.