Do you have any systems left with the issue where you haven’t already rebooted?
It’s possible that the non-debug level logging that was on when you initially encountered the issue captured some useful information. If that’s so, please use that to open a case with Duo support. This definitely isn’t expected behavior so we’d want to examine whatever artifacts you could provide.
If there are no logs available from before, but you encounter this again with future installs, please enable debugging via regedit without rebooting, reproduce the issue, and contact Duo Support to open a case.
For reference, which version of the Duo software did you install, what were the target Windows versions, and did you install Duo interactively or silently using the MSI?