Sending JSON logs to remote server

Running Fortigate v7.4.5 and I'm trying to use a datadog collector to forward my logs up to datadog but the datadog isn't able to recognize individual lines/json object as disticnt logs. I was looking at some of the raw output and I noticed that there are some characters between the 2 json objects. Does anyone know what these are?

","mpsk":"N/A","msg":"Client d2:b6:1c:6c:c2:45 authenticated.","new_line":"/n"}1557 <45>{"date":"2025-02-26","time":"09:41:55","devname":"PGH-

What is the "1557<45>" it' not part of the json object and I'm wondering if it is causing this.