A problem that has been spotted in early March has resurfaced on Twitter this week, and Lenovo pointed the troubled customer to the official forum. Sadly, the 18-page discussion about the X1 Carbon's inability to use deep sleep on Linux also reveals that Lenovo's machines are unable to use LTE and the fingerprint reader when running this operating system.
https://www.notebookcheck.net/The-6th-gen-Lenovo-ThinkPad-X1-Carbon-on-Linux-is-facing-sleep-mode-issues-unofficial-patch-available-for-a-while.316584.0.html
Deep sleep on a X1C6 is a long resolved issue. Bios update brings a setting to enable/disable Linux sleep compatibility.