Display stays on VT7 after logout, greeter renders correctly on VT8 but VT switch doesn't occur

[garyruskin]

hardware: ThinkPad X1 Carbon 5th gen, Intel HD Graphics 620
OS: Linux Mint 22.3 (Zena)
slick-greeter version: 2.2.6+zena
The exact symptom: display stays on VT7 after logout, greeter renders correctly on VT8 but VT switch doesn't occur
The key log evidence from /var/log/lightdm/lightdm.log showing Activating VT 8 succeeding but display not switching
The greeter log showing the correct background loads successfully