We have a new, vanilla 2016 server running hyper-v. It is patched current to: July 9, 2019—KB4507460 (OS Build 14393.3085)
On boot up post adding the virtual switch to the Hyper-V server the network comes up with the yellow triangle. If we connect via the iDRAC and disable the Virtual Network Adapter - MGT and then re-enable the network starts working again, until the next reboot.
Any ideas?