If I set a stored procedure field to type of JSON, whenever I try to debug the stored procedure, I get the error:
Cannot create a JSON value from a string with CHARACTER SET 'binary'.
Note this ONLY happens when trying to debug a Stored Procedure with the Studio debug interface, as seen below. Note the JSON data type is selected:

To fix it? I just change in_JSON to a TEXT type. It's also important to note the EDIT PARAMETERS dialogue doesn't have a JSON data type selectable, only TEXT.
Another issue is the JSON processed with the debugger is tossing a ton of \ in the values, as seen below:

Note entries 13 and above are created by my system; 14, 15 and 16 are from the debugger.