Sort JSON data field by month year

[RickCogley]

This might have a hint:

[Solved] GroupByParamDate produces "runtime error: index out of range"

You’ll need to first share your site source (at least a minimal version if you cannot share the original site), so that someone can clone it and reproduce the issue on their machine, and debug better.

Besides that, it’s come up before about passing the wrong type of data to a given function. Like expecting a date to be sortable by these sorts of functions but, actually passing them a string that they can’t parse.