Hurricane Electric has informed us of an impending maintenance event. In their words:
Reason: Router software maintenance to enhance security and stability
Window Start Time: Tuesday, August 20, 2019 00:01 (UTC-0700)
Window End Time: Tuesday, August 20, 2019 04:00 (UTC-0700)
Expected Impact: < 1 hour
We do not expect significant issues during the impact time, but the network may be degraded as routes go over our slower backup link. HE has had unplanned emergency router reboots in the past without us noticing.