Occasionally I notice that my computer won't suspend and then when I wake the monitor and log in, it's as if it rebooted. All applications are closed except MS Teams, which is set to auto-launch at startup. However, System Monitor shows 4+ GB memory in use, but a clean boot after Teams launches will typically show only about 2 GB in use. So it's like it rebooted, but there is still some memory leakage, which seems like it didn't do a clean reboot and reclaim all the memory. Any idea what is going on here and if it is rebooting by itself, why? A self-reboot without log-in would explain why it doesn't suspend as I think a user has to be logged in to suspend, otherwise it's still in a "boot" state. I have my automatic suspend set to 15 minutes. I do have my security updates set to download and install automatically, but would the system reboot itself automatically after an update as well?
I built this system about a year ago 2021:
Ubuntu 20.04.4 LTS
AMD 5600X (no overclock set yet)
Corsair H60 Liquid Cooler
ASUS TUF Gaming X570-Plus WiFi
2 x 16 GB G_Skill DDR4-3200
XFX Radeon HD 7870 (repurposed from my old computer to this build)
Western Digital WD Blue SN550 NVMe SSD