My connections dropped twice (that I've noticed) in the last half hour.

2016-09-15 21:16:01 User Level Notice Action GetTotalBytesSent from  executed by UPNP/TR064 successfully.
2016-09-15 21:15:53 User Level Notice CWMP:Cwmp post inform success.
2016-09-15 21:15:52 System Notice Message type: Query, Querier: 192.168.10.254, Group: 0.0.0.0, version: 3.
2016-09-15 21:15:52 User Level Notice CWMP inform message: parameter change.
2016-09-15 21:15:52 User Level Notice CWMP inform message: event: 4 VALUE CHANGE.
2016-09-15 21:15:47 System Notice WAN connection INTERNET_UMTS:IPv4 connected.
2016-09-15 21:15:47 System Notice PPP IPCP received Configuration Ack.
2016-09-15 21:15:47 System Notice PPP IPCP sent Configuration Request.
2016-09-15 21:15:47 System Notice PPP IPCP received Configuration Reject.
2016-09-15 21:15:47 System Notice PPP IPCP received Configuration Nak.
2016-09-15 21:15:47 System Notice PPP IPCP sent Configuration Request.
2016-09-15 21:15:47 System Notice PPP IPCP received Configuration Reject.
2016-09-15 21:15:47 System Notice PPP IPCP sent Configuration Ack.
2016-09-15 21:15:47 System Notice PPP IPCP received Configuration Request.
2016-09-15 21:15:47 System Notice PPP IPCP sent Configuration Request.
2016-09-15 21:15:47 System Notice PPP PAP authentication succeeded.
2016-09-15 21:15:47 System Notice PPP LCP received Configuration Ack.
2016-09-15 21:15:47 System Notice PPP LCP sent Configuration Ack.
2016-09-15 21:15:47 System Notice PPP LCP received Configuration Request.
2016-09-15 21:15:47 System Notice PPP LCP sent Configuration Request.
2016-09-15 21:15:44 System Notice DNS query failed: Name: www.google.com, Type: 1, Error: time out
2016-09-15 21:15:44 System Notice DNS query failed: Name: www.google.com, Type: 28, Error: time out
2016-09-15 21:15:44 System Notice DNS query failed: Name: www.google.com, Type: 1, Error: time out
2016-09-15 21:15:44 System Notice DNS query failed: Name: www.google.com, Type: 1, Error: time out
2016-09-15 21:15:42 System Notice PPP LCP sent Termination Request.
2016-09-15 21:15:40 System Notice DNS query failed: Name: www.google.com, Type: 1, Error: time out
2016-09-15 21:15:39 System Notice PPP LCP sent Termination Request.
2016-09-15 21:15:39 System Notice WAN connection INTERNET_UMTS:IPv4 disconnected.(ERROR_NO_CARRIER)
2016-09-15 21:15:39 User Level Notice Action GetTotalBytesReceived from  executed by UPNP/TR064 successfully.

Ironically the second time it happened was while I was about to download a syslog server since the router logs retention seems limited.