Why CustomAudienceSession is always uploading after I make the last batch flag as true

[liyueshining]

new CustomAudience(audienceId, context).getSessions()
.setSessionId(sessionId)
.execute().head();

Response:
{"data":[{"session_id":"653573199724136401","start_time":"1757326241","end_time":"0","num_received":"10000","num_matched":"-1","num_invalid_entries":"0","progress":"0","stage":"uploading"}]}