Might be unrelated but this could also be a reason:
https://social.technet.microsoft.com/Forums/office/en-US/c277b434-fb99-4694-9933-15fbe3761e70/no-network-activity-for-60-sec-after-a-destination-host-unreachable-error?forum=w7itpronetworking
Multiple LAN cards and using more than one default gateway (ARP/MAC ‘blocking’).
https://social.technet.microsoft.com/Forums/office/en-US/c277b434-fb99-4694-9933-15fbe3761e70/no-network-activity-for-60-sec-after-a-destination-host-unreachable-error?forum=w7itpronetworking
Multiple LAN cards and using more than one default gateway (ARP/MAC ‘blocking’).