An update:
I've nailed down further information on the issue since it keeps happening:
When the issue occurs, I see the following in the Windows Event Viewer Application log (details below):
 

The description for Event ID 26 from source Application Popup cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.
If the event originated on another computer, the display information had to be saved with the event.
The following information was included with the event:
\??\C:\Program Files (x86)\EVGA\NU Audio Card Pro\NUREGx64.sys failed to load
Element not found

- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
  <Provider Name="Application Popup" Guid="{47bfa2b7-bd54-4fac-b70b-29021084ca8f}" EventSourceName="Application Popup" /> 
  <EventID Qualifiers="16384">26</EventID> 
  <Version>0</Version> 
  <Level>4</Level> 
  <Task>0</Task> 
  <Opcode>0</Opcode> 
  <Keywords>0x80000000000000</Keywords> 
  <TimeCreated SystemTime="2020-07-24T17:20:52.9435030Z" /> 
  <EventRecordID>17739</EventRecordID> 
  <Correlation /> 
  <Execution ProcessID="4" ThreadID="6080" /> 
  <Channel>System</Channel> 
  <Computer>DARK</Computer> 
  <Security /> 
  </System>
- <EventData>
  <Data /> 
  <Data>\??\C:\Program Files (x86)\EVGA\NU Audio Card Pro\NUREGx64.sys failed to load</Data> 
  <Binary>0000000002003000000000001A000040280400C06C0200C000000000000000000000000000000000</Binary> 
  </EventData>
  </Event>

Of further note, if I open the Nu Audio Pro control panel and click on the speaker icon, I hear no audible *click* from the card. Adjusting the system or mixer volume/muting in Windows 10 has no effect. I can only adjust those settings from the NU Audio Control Panel. I also cannot seem to change between the speaker and headphone output even though the corresponding source 'lights up'.
 
Restarting Windows usually helps, but sometimes I need to restart more than once to get it working again.
 
OS: Windows 10 Pro build 19042.487
 
Anyone else seeing this or something similar?

It looks like its trying to boot the x64 nu driver from the x86 folder, which its not supposed to be doing. You sure you have the right download?
 
EDIT: very bottom of log;  "<Data>\??\C:\Program Files (x86)\EVGA\NU Audio Card Pro\NUREGx64.sys failed to load</Data>"