Ubuntu 20.04 Server installer crashes while looking for updated installer when a network interface exists that does not have Internet access

[Lucas]

Summary:
I attempted to install Ubuntu 20.04 Server on a Hyper-V virtual machine. I configured the VM with two network interfaces, one facing my regular, "real" network, the other facing an internal (not private) network--with no route to the Internet. When the installer ran, the external interface mapped to eth0 and DHCP provided the correct information; the internal interface mapped to eth1 and DHCP provided the correct information.

While 'snap' was 'looking for a newer version of the installer', the system restarted, and when the installer opened again it informed me that it had crashed. I tried to browse the crash report to find the actual error, but honestly I got tired of trying to scroll through all the chaff (I apparently held down End too long, and it never stopped scrolling). I also tried to 'send the error report to Canonical', which caused another crash.

At this point I restarted, and in the installer's network interface configuration, I disabled the internal interface. After this the installer proceeded normally.

Of course, the actual cause is speculative since I don't have an error report, but it seems likely that the installer or some component of it tried to use the eth1 interface to 'look for a newer version of the installer', and did not gracefully fail when it turned out to be impossible to reach the Internet through said interface.

What I expected to happen:
Installer continues normally.

What actually happened:
Installer crashed.

'lsb_release -rd':
Description: Ubuntu 20.04 LTS
Release: 20.04

Version of Package:
I don't know what the package was.

[Zhanglei Mao (zhanglei-mao)]

One or our partner report it to me too:
  20.04.0 and 20.04.1 would fail
  20.04.5 works well