Javascript error on Greenhopper boards after upgrade

After recent upgrade to the latest Greenhopper version 6.1.3.1, the following Greenhopper error appears :

Details
Exception: Script error.
Resource: https://jira.atlassian.com/s/en_UKsx8qk0/710/2/1.0.8-beta/_/download/batch/com.atlassian.jira.collector.plugin.jira-issue-collector-plugin:issuecollector/com.atlassian.jira.collector.plugin.jira-issue-collector-plugin:issuecollector.js
Line: 0

It seems the error only occurs in Firefox.

The error disappears from the screen after refreshing the page.