Hi,
This seems to be a bug, as multiple users have reported running into the same issue. Based on those reports, it appears to affect both Android and iOS devices. You can check the thread below for reference.
https://learn.microsoft.com/en-us/answers/questions/5866490/phone-link
You can try the usual steps like resetting the apps on both devices and linking them again. If it doesn't work, there’s not much more you can do on your end for now. The best next step is to report it so the developers can look into it and fix it in a future update. You can send feedback directly through both the Link to Windows and Phone Link apps to make sure it reaches the right channel.