Likely leftover old drivers. Use a driver cleaner like Display Driver Uninstaller (DDU) in audio device mode, or manually delete C:\Program Files\Plantronics and registry entries under HKEY_LOCAL_MACHINE\SOFTWARE\Plantronics , then retry.
Click the update button to install the latest firmware, which often resolves issues with the speaker, microphone, or call control buttons. Troubleshooting Common Issues Plantronics USB Headset Not Working Properly plantronics p610 driver
Plantronics is now Poly (acquired by HP). As a result, official drivers for legacy products like the P610 are hosted on the Poly support website, not the old Plantronics domain. Likely leftover old drivers