Thank you for reaching out to us, I am sorry this is not working as expected and I am happy to help!
We have had similar reports from other Surface Pro 7 users that the dock will be unstable after returning from a low power state ( waking from sleep, or powering on using Windows Fast Startup ) and even sometimes when rebooting.
We believed this issue had been resolved by a Surface Pro 7 firmware update back in March, however it appears to be a reoccurring issue with the latest firmware updates for this system.
This behavior is limited to our UD-CA1A docking station and has not been duplicated with our other USB-C docking stations and I can recommend our UD-CAM USB-C Mini Docking Station ( https://plugable.com/products/ud-cam ) for use with the Surface Pro 7. I would be happy to help return the UD-CA1A within our 30-day return period, please email our support team directly at ‘email@example.com’ with the subject line ‘Ticket #318373 - Attention Pat’ and let me know your Amazon Order ID ( available from Amazon.com/orders ) and I will help to get the return process started for this docking station.
I am sorry for the inconvenience and look forward to your reply email.