Odd mount behavior: Swap, ESP

I'm suddenly observing some odd mount behavior that is affecting both the swap and EFI system partitions, among others. The system is Lubuntu 20.04.4 in a GRUB multi-boot configuration with Ubuntu Desktop (i.e., GNOME3) 20.04.4 on another partition. All partitions are on a single, unencrypted volume.

Initially, I got an error in launching VMware Workstation suggesting/insisting that swap be enabled. This seemed odd because a swap partition is configured in fstab. Sure enough,

swapon -s

returned no output and

cat /proc/swaps

returned no entries. Doing

swapon -a

fixed this although the configuration did not persist through reboot.

The GRUB menu then did not appear as it had until then, so I checked /etc/default/grub, ran update-grub, and to be safe, grub-install, which returned:

grub-install: error: cannot find EFI directory.

This also seemed odd because the ESP also is mounted to /boot/efi in fstab.

Several other, but not all, partition mounts also failed. The one that works contains /home.

Even more curiously, in the terminal emulator, I can recursively navigate to /boot/efi/EFI and its subdirectories. After so doing, grub-install returns:

Installation finished. No error reported.

So, the system seems to be automounting, instead of mounting, partitions.

WTF??? Any thoughts about why this might be occurring or how to fix it would be most appreciated.