Hanging script

[StP]

If I log into OPNsense, navigate to the dashboard and just leave it alone for some hours I get an error message about a hanging script. This is the link mentioned in the error box:

https://172.16.30.1/ui/js/d3.min.js:2

My dashboard shows:
- Traffic graph
- Interface statistics
- System information
- Interface list

OPNsense 16.7.1
Browser: Firefox 48.0

Regards
  Stefan