Nowadays, I get something in this pattern:

{"running":"false","duration":13500,"startDate":1707304409}

While previously it was more comprehensive:

{"running":false,"duration":27000,"startDate":1692279168,"additional_value":[{"id":431055371,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-06-12T10:00:00Z","ended_at":"2023-06-12T10:30:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055372,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-06-13T21:00:00Z","ended_at":"2023-06-13T22:00:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055373,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-06-14T21:00:00Z","ended_at":"2023-06-14T23:00:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055374,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-08-03T21:00:00Z","ended_at":"2023-08-03T22:00:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055375,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-08-06T21:00:00Z","ended_at":"2023-08-06T21:30:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055376,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-08-10T21:00:00Z","ended_at":"2023-08-10T22:00:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055377,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-08-13T22:00:00Z","ended_at":"2023-08-13T23:00:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"},{"id":431055378,"account_id":14146675,"project_id":5006004908,"column_id":"time_tracking","started_user_id":43990043,"ended_user_id":43990043,"started_at":"2023-08-16T21:00:00Z","ended_at":"2023-08-16T21:30:00Z","manually_entered_start_time":true,"manually_entered_end_time":true,"manually_entered_start_date":true,"manually_entered_end_date":true,"created_at":"2023-08-17T14:17:55Z","updated_at":"2023-08-17T14:17:55Z","status":"active"}]}

if you further add the following to the item query, it will return the data as it was:

column_values {
      ... on TimeTrackingValue {
        id
        history
      }
    }

Ref: https://developer.monday.com/api-reference/reference/time-tracking
https://developer.monday.com/api-reference/reference/other-types#time-tracking-history-item