The Assistant did not reply

Sometimes the run status of the Assistant is “completed”, but there is no reply from the Assistant in the message list.
For example, in the data below, the first user did not receive a response from the Assistant.
{
“data”: [
{
“id”: “…”,
“object”: “thread.message”,
“role”: “user”,
“content”: [
{
“type”: “text”,
“text”: {
“value”: “有分公司吗”,
“annotations”:
}
}
],
“metadata”: {},
“created_at”: 1702547497,
“thread_id”: “…”,
“file_ids”:
},
{
“id”: “…”,
“object”: “thread.message”,
“role”: “assistant”,
“content”: [
{
“type”: “text”,
“text”: {
“value”: “根据 xxx.pdf文件,…”,
“annotations”: [
{
“type”: “file_citation”,
“text”: “【253†source】”,
“file_citation”: {
“quote”: “# …”,
“file_id”: “file-…”
},
“start_index”: 60,
“end_index”: 72
}
]
}
}
],
“metadata”: {},
“created_at”: 1702547483,
“thread_id”: “…”,
“assistant_id”: “…”,
“run_id”: “…”,
“file_ids”:
},
{
“id”: “…”,
“object”: “thread.message”,
“role”: “user”,
“content”: [
{
“type”: “text”,
“text”: {
“value”: “我们公司大约有多少员工”,
“annotations”:
}
}
],
“metadata”: {},
“created_at”: 1702547444,
“thread_id”: “…”,
“file_ids”:
}
],
“object”: “…”,
“first_id”: “…”,
“last_id”: “…”,
“has_more”: true
}