Daily Activity Summary calories in "activities" returns string instead of number

[hi_SG]

We have recently received Daily Activity Summary's activities.calories is returning a string ("-23") instead of -23, eg:

{
  ...
    "activities" : [{
        ...
        "calories": "-23"
    }],
}

This behavior does not align with what was defined in the documentation (https://dev.fitbit.com/build/reference/web-api/activity/get-daily-activity-summary/) where calories is expected to be of Number type. 

Is this an intentional change or a bug? Thanks.