Hello H_386,
Welcome to Microsoft Community.
According to your description of the problem, after connecting the Type Cover to your Surface Pro6, your Surface Pro6 will still randomly change to tablet mode?
Judging from the symptoms, I think this is caused by the poor contact between the connection port at the lower end of Surface Pro 6 and the Type Cover. If you're using a Surface Pro 6 with Windows 11, Windows 11 has removed the option to manually change tablet mode, so if the Surface doesn't recognize the professional keyboard cover, it will display in tablet mode.
The first thing I recommend you try to do is try to clean the contacts with a soft, dry, lint free cloth and check the ports for foreign objects. After cleaning, reconnect the Type cover to your Surface Pro 6 and see if the problem reappears.
If you notice that this issue is not improving, I recommend that you try downloading and manually installing the driver and firmware package for the Surface Pro 6, in order to rule out the possibility of driver failure:
Download Surface Pro 6 Drivers and Firmware from Official Microsoft Download Center ****
Once manually downloaded and installed, restart your Surface Pro 6 and continue to observe the situation
But if in the end you find that the problem cannot be improved by these solutions, then I am afraid it is a hardware fault. I'm more inclined to judge this as a Type Cover problem than the Surface itself.
I would have recommended that you contact Surface Technical support to have your device repaired, but since this model has been discontinued, out-of-warranty support and service will no longer be available. We appreciate your commitment to Surface and apologize for any inconvenience.
We'd love to help you upgrade to a new, more capable device. Please check out our****online Microsoft Store, visit one of our locations in person, or chat with an expert to learn about ongoing and special promotions.
However, perhaps I can give you an additional suggestion, try to buy a Surface Pro 6 Type Cover to replace the Type Cover you are using, because it is cheaper than buying a new device. But the corresponding Type Cover of the official mall has been out of stock:
Microsoft Surface Pro Type Cover | Surface Pro Keyboard - Microsoft Store ****
So, it might be worth referring you to Amazon to see if some third-party resellers still have it in stock.
Best Regards,
Mitchell | Microsoft Community Support Specialist