jira-trigger-webhook-receiver throws JSONException: JSONObject["name"] not found - jenkins-jira-trigger

Question

We have JIRA triggering Jenkins builds using jira-trigger plugin of Jenkins. AS of yesterday(2019-07-10) it was all working but today it is not triggering any builds.
I have enabled following logging (to all) in Jenkins and checked the logs
*com.ceilfors.jenkins.plugins.jiratrigger.*
com.ceilfors.jenkins.plugins.jiratrigger.webhook.JiraWebhook
com.ceilfors.jenkins.plugins.jiratrigger.JiraCommentTrigger
com.ceilfors.jenkins.plugins.jiratrigger.JiraTrigger
com.ceilfors.jenkins.plugins.jiratrigger.JiraTriggerExecutor*
I could see Jira webhook is sending valid JSON and same is failing at Jenkins stating this error: org.codehaus.jettison.json.JSONException: JSONObject["name"] not found.
Error while serving https://localhost/jira-trigger-webhook-receiver/
org.codehaus.jettison.json.JSONException: JSONObject["name"] not found.
at org.codehaus.jettison.json.JSONObject.get(JSONObject.java:360)
at org.codehaus.jettison.json.JSONObject.getString(JSONObject.java:487)
at com.atlassian.jira.rest.client.internal.json.JsonParseUtil.parseBasicUser(JsonParseUtil.java:192)
at com.atlassian.jira.rest.client.internal.json.CommentJsonParser.parse(CommentJsonParser.java:37)
at com.atlassian.jira.rest.client.internal.json.CommentJsonParser$parse.call(Unknown Source)
at com.ceilfors.jenkins.plugins.jiratrigger.webhook.WebhookCommentEventJsonParser.parse(WebhookCommentEventJsonParser.groovy:40)
at com.ceilfors.jenkins.plugins.jiratrigger.webhook.WebhookCommentEventJsonParser$parse.call(Unknown Source)
at com.ceilfors.jenkins.plugins.jiratrigger.webhook.JiraWebhook.processEvent(JiraWebhook.groovy:71)
at com.ceilfors.jenkins.plugins.jiratrigger.webhook.JiraWebhook$processEvent.callCurrent(Unknown Source)
at com.ceilfors.jenkins.plugins.jiratrigger.webhook.JiraWebhook.doIndex(JiraWebhook.groovy:51)
at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
Caused: java.lang.reflect.InvocationTargetException
at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:400)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:408)
at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:77)
at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:212)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:145)
at org.kohsuke.stapler.IndexDispatcher.dispatch(IndexDispatcher.java:27)
JSON Received:
{
"timestamp": 1562845569917,
"webhookEvent": "comment_created",
"comment": {
"self": "https://my.atlassian.net/rest/api/2/issue/12815/comment/19186",
"id": "19186",
"author": {
"self": "https://my.atlassian.net/rest/api/2/user?accountId=1234567890",
"accountId": "1234567890",
"emailAddress": "\"?\"",
"avatarUrls": {
"48x48": "https://alocal.net/initials/PM-1.png?size=48&s=48",
"24x24": "https://alocal.net/initials/PM-1.png?size=24&s=24",
"16x16": "https://alocal.net/initials/PM-1.png?size=16&s=16",
"32x32": "https://alocal.net/initials/PM-1.png?size=32&s=32"
},
"displayName": "admin",
"active": true,
"timeZone": "Asia/Calcutta",
"accountType": "atlassian"
},
"body": "deploy_staging",
"updateAuthor": {
"self": "https://my.atlassian.net/rest/api/2/user?accountId=1234567890",
"accountId": "1234567890",
"emailAddress": "\"?\"",
"avatarUrls": {
"48x48": "https://alocal.net/initials/PM-1.png?size=48&s=48",
"24x24": "https://alocal.net/initials/PM-1.png?size=24&s=24",
"16x16": "https://alocal.net/initials/PM-1.png?size=16&s=16",
"32x32": "https://alocal.net/initials/PM-1.png?size=32&s=32"
},
"displayName": "admin",
"active": true,
"timeZone": "Asia/Calcutta",
"accountType": "atlassian"
},
"created": "2019-07-11T17:16:09.917+0530",
"updated": "2019-07-11T17:16:09.917+0530",
"jsdPublic": true
},
"issue": {
"id": "12815",
"self": "https://my.atlassian.net/rest/api/2/issue/12815",
"key": "DEVOPS-160",
"fields": {
"summary": "Deploy - Test",
"issuetype": {
"self": "https://my.atlassian.net/rest/api/2/issuetype/10081",
"id": "10081",
"description": "",
"iconUrl": "https://my.atlassian.net/secure/viewavatar?size=medium&avatarId=10304&avatarType=issuetype",
"name": "Deployment",
"subtask": false,
"avatarId": 10304
},
"project": {
"self": "https://my.atlassian.net/rest/api/2/project/10032",
"id": "10032",
"key": "DEVOPS",
"name": "Test Ops",
"projectTypeKey": "software",
"simplified": false,
"avatarUrls": {
"48x48": "https://my.atlassian.net/secure/projectavatar?pid=10032&avatarId=10517",
"24x24": "https://my.atlassian.net/secure/projectavatar?size=small&s=small&pid=10032&avatarId=10517",
"16x16": "https://my.atlassian.net/secure/projectavatar?size=xsmall&s=xsmall&pid=10032&avatarId=10517",
"32x32": "https://my.atlassian.net/secure/projectavatar?size=medium&s=medium&pid=10032&avatarId=10517"
},
"projectCategory": {
"self": "https://my.atlassian.net/rest/api/2/projectCategory/10006",
"id": "10006",
"description": "Operations",
"name": "Operations"
}
},
"assignee": {
"self": "https://my.atlassian.net/rest/api/2/user?accountId=1234567890",
"name": "phani.k",
"key": "phani.k",
"accountId": "1234567890",
"emailAddress": "phani.k#synup.com",
"avatarUrls": {
"48x48": "https://alocal.net/1234567890/dfe77db8-e320-4c3e-a074-3d79892a5c6d/128?size=48&s=48",
"24x24": "https://alocal.net/1234567890/dfe77db8-e320-4c3e-a074-3d79892a5c6d/128?size=24&s=24",
"16x16": "https://alocal.net/1234567890/dfe77db8-e320-4c3e-a074-3d79892a5c6d/128?size=16&s=16",
"32x32": "https://alocal.net/1234567890/dfe77db8-e320-4c3e-a074-3d79892a5c6d/128?size=32&s=32"
},
"displayName": "admin",
"active": true,
"timeZone": "Asia/Kolkata",
"accountType": "atlassian"
},
"priority": {
"self": "https://my.atlassian.net/rest/api/2/priority/3",
"iconUrl": "https://my.atlassian.net/images/icons/priorities/medium.svg",
"name": "Medium",
"id": "3"
},
"status": {
"self": "https://my.atlassian.net/rest/api/2/status/10118",
"description": "Run all feasibility checks",
"iconUrl": "https://my.atlassian.net/",
"name": "In Progress",
"id": "10118",
"statusCategory": {
"self": "https://my.atlassian.net/rest/api/2/statuscategory/4",
"id": 4,
"key": "indeterminate",
"colorName": "yellow",
"name": "In Progress"
}
}
}
}
}