Welcome back to Poly Community !!
I would suggest you to directly connect BT600 with your PC instead of using any docking stations, splitters, or hubs.
If you still encounter the issue, kindly open a support ticket with Poly as there are various components involved here & may require further investigation to find out the root cause.
Please ensure you always check the FAQ's.
Please remember, if you see a post that helped you, and it answers your question, please mark it as an "Accept as Solution".
This forum reply or post is based upon my personal experience and does not reflect the opinion or view of my employer. Poly employee participation within this community is not mandatory and any post or FAQ article provided by myself is done either during my working hours or outside working hours, in my private time, and may be answered on weekends, bank holidays or personal holidays.