MX 17.10.2 WAN interfaces dropping

[cmr]

We have about 20 HA pairs and single MXs combined, most are running 17.10.2 and have been since shortly after it was released.

In the last week two separate setups, the spare appliance of an MX84 pair in IPv4 only mode and a standalone MX75 in dual stack mode have both had one WAN show as failed even though the port is up.  Trying to ping the default gateway of that connection fails, but rebooting the MX fixes it...

Has anyone else seen this behaviour as it's new to me? 😮

[PhilipDAth]

Remember - it has to pass all the WAN connectivity tests to be considered up.

https://documentation.meraki.com/MX/Firewall_and_Traffic_Shaping/Connection_Monitoring_for_WAN_Failo... 

Perhaps something else is failing, like DNS.

[cmr]

The same DNS is used for all 4 connections on the HA pair and with the other it is directly on the internet and using the providers local DNS (same for all sites).  It was down for about a month, yet a reboot fixed it straight away...  I smell a bug 🐛