_update_by_query + script do not work correctly，error:Trying to create too many scroll contexts - elasticsearch

Question

Elasticsearch version: 7.6.2
JVM：13.0.2
OS version：centeros7
This is my code
POST recommend_index/_update_by_query
{
"script": {
"source": "ctx._source.rec_doctor_id = 1"
},
"query": {
"bool": {
"must": [{
"terms": {
"id": ["22222"]
}
}]
}
}
}
This code does not return the result correctly,The error message is
{
"error": {
"root_cause": [
{
"type": "exception",
"reason": "Trying to create too many scroll contexts. Must be less than or equal to: [5000]. This limit can be set by changing the [search.max_open_scroll_context] setting."
}
],
"type": "search_phase_execution_exception",
"reason": "Partial shards failure",
"phase": "query",
"grouped": true,
"failed_shards": [
{
"shard": 1,
"index": "recommend_index",
"node": "XXX",
"reason": {
"type": "exception",
"reason": "Trying to create too many scroll contexts. Must be less than or equal to: [5000]. This limit can be set by changing the [search.max_open_scroll_context] setting."
}
}
]
},
"status": 500
}
I'm sure the current scroll is 0
When I replace _UPDATE_BY_QUERY with _UPDATE, it updates normally
No change has been made in ES since last Friday, and suddenly an error is reported
No configuration changes have been made to the ES server

Answer 1

follow-up:
I set the search.max_open_scroll_context parameter to 5000 and found nothing to do with it.
I looked up the 7.6.2 release and found that someone was having the same problem as me.Link on this
here #71354 #56202
I guess this is due to scrolling triggering the 7.6.2 bug.I restarted the cluster node without upgrading and found that it worked!!