Timestamp long was not converted into date format

Versions (relevant - OpenSearch/Dashboard/Server OS/Browser):

OpenSearch version : 2.5.0
TARGET OS : Red Hat Enterprise Linux 8.4 (Ootpa)

Describe the issue:

The KPIs are collected from redhat machine and send to Openseach,
We are sending a “@timestamp” : 1732789307000 , most of the times opensearch detect and auto convert the long into date.But some case the long was ingested without being converted .

Configuration:

Relevant Logs or Screenshots:
{ “successful” : 10, “running” : 0, “ready” : 0, “error” : 2 , “waiting” : 0, “blocked” : 0, “held” : 18, “@timestamp” : 1732789307000 }