Below is the log captured at the time of Graylog attempting to send a webhook.
{"level":30,"time":"2022-04-24T01:33:21.190Z","pid":32448,"hostname":"RC-Server","name":"Integrations","section":"Incoming WebHook","msg":"Post integration:","name":"Graylog-Webhook"}
{"level":30,"time":"2022-04-24T01:33:21.191Z","pid":32448,"hostname":"RC-Server","name":"Integrations","section":"Incoming WebHook","msg":"Will evaluate script of Trigger","name":"Graylog-Webhook"}
{"level":50,"time":"2022-04-24T01:33:21.193Z","pid":32448,"hostname":"RC-Server","name":"Integrations","section":"Incoming WebHook","msg":"Error running Script in Trigger","name":"Graylog-Webhook","script":"var GRAYLOG_URL=\"https://Graylog-Server.com:9000\";var createPermalink=function(m,index){var label=index===0?\"Display complete message\":\"#\"+(index+1);return\"[\"+label+\"](\"+GRAYLOG_URL+\"/messages/\"+m.index+\"/\"+m.id+\")\"};var formatMessages=function(messages){var grouped=messages.reduce(function(acc,m){if(!acc.hasOwnProperty(m.message)){acc[m.message]=[]}acc[m.message].push(m);return acc},{});var result=[];for(var mType in grouped){if(grouped.hasOwnProperty(mType)){var line=\"*Message*: \"+mType+\"\<br>*Source*: \"+grouped[mType][0].source+\"\<br>\"+grouped[mType].map(createPermalink).join(\", \");result.push(line)}}return result.join(\"\<br>-------------\<br>\")};var parseText=function(result){if(result.matching_messages.length>0){return formatMessages(result.matching_messages)}else{return result.result_description}};var createAlertMessageEvent=function(result){return\":warning: *Alert*: \"+result.triggered_condition.title+\"\<br>\"+parseText(result)};var makeAttachment=function(text){return{text:text,color:\"#e8d612\"}};var Script=function(){function Script(){}var _proto=Script.prototype;_proto.process_incoming_request=function process_incoming_request(_ref){var request=_ref.request;return{content:{attachments:[makeAttachment(createAlertMessageEvent(request.content.check_result))]}}};return Script}();","err":{},"msg":"TypeError: Cannot read property 'triggered_condition' of undefined"}
{"level":35,"time":"2022-04-24T01:33:21.194Z","pid":32448,"hostname":"RC-Server","name":"API","method":"POST","url":"/hooks/727d4cf65fd626491526f828/zyTEobhd78f7LWB5yKmpJuA8sG56SMgwJzHoTBss5XSkhApd","userAgent":"okhttp/3.14.6","length":"2209","host":"RC-Server.com:3000","remoteIP":"x.x.x.x","status":400,"responseTime":4}