We also use and ping your servers for our network device WAN link monitoring.
On 29th Dec, 2018, we found that there was high ping latency / time out from 188.8.131.52 and 184.108.40.206 server,
This also triggered our wan link to fail-over to another link.
At the same time, nothing wrong with google ping response.
Might I confirm what was the issue on it?