Message is getting truncated

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

Describe the issue:
I am using Serilog.Sinks.OpenSearch. When writing complex JSON strings in a message. It is getting truncated. But the same text is written in MEssageTemplate.
Attached screenshot for your reference. (one last curly braces is getting truncated.)

Configuration:

Relevant Logs or Screenshots:

OpenSearch has no way to truncate the text except there’s a custom ingest pipeline which can pre-process the document, so you may check if ingest pipeline is used when indexing the documents or there’s other pre-process tool executes before indexing into OpenSearch.

Can you share us the mapping of indices that the truncated documents are ingested?