Hi Rajeev,

I tested the core examples  with a USB  Logitech camera (Logitech Quickcam Pro 9000 with resolution : (960 by 720)) , Unity 2020.3.4f1 and Vuforia(9.8.5 (Current) - released on March 15, 2021)- and there was no issue 

Used the Windows 10 default driver provided by plug and play. I did not install any special drivers.

The camera work very stable also in Unity play mode - e.g. tested the Vuforia Core examples in the Untiy Asset store , ->scene "3-ObjectReco   in the folder Assets>SamplesResources> Scenes

So , I think this seems not to be a general issue but possibly:

- your driver version of the camera and try to update it if new version available

- possible a check with second device / if you have such available -

- try to use the default window driver / only for testing to be sure that issue is no driver specific/ or try to downgrade for testing the resolution 

additonally I will try soon to update to latest Unity version and the latest Vuforia engine and will test it again that this is not issue specific to the last version

Best Regards

Vuforia Engine Support

Now installed Unity version 2020.38f1 und updated the Vuforia in the core example to  Vuforia Version 9.8.8.

I tested but was not able to reproduce any problems - the USB camera was working fine. - So this means that the change of the version is here not really relevant (at least for my camera – but it is form the same product family - possibly because my camera is older  there is the  resolution is lower comparing to your camera.

Another trivial point to check – windows camera settings

BR