Update-grub lists multiple entries, but grub.cfg lists only actually exist ones

Here’s what update-grub spits when I execute it:

$ sudo update-grub
Generating grub configuration file …
Found theme: /boot/grub/themes/Archxion/theme.txt
Found linux image: /boot/vmlinuz-5.9-x86_64
Found initrd image: /boot/intel-ucode.img /boot/initramfs-5.9-x86_64.img
Found initrd fallback image: /boot/initramfs-5.9-x86_64-fallback.img
Found linux image: /boot/vmlinuz-5.8-x86_64
Found initrd image: /boot/intel-ucode.img /boot/initramfs-5.8-x86_64.img
Found initrd fallback image: /boot/initramfs-5.8-x86_64-fallback.img
Found linux image: /boot/vmlinuz-5.4-x86_64
Found initrd image: /boot/intel-ucode.img /boot/initramfs-5.4-x86_64.img
Found initrd fallback image: /boot/initramfs-5.4-x86_64-fallback.img
Found Windows Boot Manager on /dev/nvme0n1p1@/EFI/Microsoft/Boot/bootmgfw.efi
Found Manjaro Linux on /dev/nvme0n1p3
Found Debian GNU/Linux 9 (stretch) on /dev/nvme0n1p3
Found Debian GNU/Linux 8 (jessie) on /dev/nvme0n1p3
Found Debian GNU/Linux 9 (stretch) on /dev/nvme0n1p3
Found Debian GNU/Linux 8 (jessie) on /dev/nvme0n1p3
Found Debian GNU/Linux 10 (buster) on /dev/nvme0n1p3
Found Debian GNU/Linux 9 (stretch) on /dev/nvme0n1p3
Found Debian GNU/Linux 9 (stretch) on /dev/nvme0n1p3
Found Debian GNU/Linux 10 (buster) on /dev/nvme0n1p3
Found Debian GNU/Linux 9 (stretch) on /dev/nvme0n1p3
Found Debian GNU/Linux 10 (buster) on /dev/nvme0n1p3
Found Debian GNU/Linux 8 (jessie) on /dev/nvme0n1p3
Found Debian GNU/Linux 8 (jessie) on /dev/nvme0n1p3
Found Pearl 7.1 Rolltide LTS (7.1) on /dev/nvme0n1p4
Adding boot menu entry for UEFI Firmware Settings …
Found memtest86+ image: /boot/memtest86+/memtest.bin
/usr/bin/grub-probe: warning: unknown device type nvme0n1.
done

The bold ones don’t eventually get into /boot/grub/grub.cfg, though, which is correct as I have no Debian installed (Manjaro, Pearl, Android x86 and Windows only) as this illustrates:

$ sudo grep menuentry /boot/grub/grub.cfg
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="–id"
menuentry_id_option=""
export menuentry_id_option
menuentry ‘Manjaro Linux’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-simple-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
submenu ‘Advanced options for Manjaro Linux’ $menuentry_id_option ‘gnulinux-advanced-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Manjaro Linux (Kernel: 5.9.3-1-MANJARO x64)’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-5.9.3-1-MANJARO x64-advanced-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Manjaro Linux (Kernel: 5.9.3-1-MANJARO x64 - fallback initramfs)’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-5.9.3-1-MANJARO x64-fallback-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Manjaro Linux (Kernel: 5.8.18-1-MANJARO x64)’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-5.8.18-1-MANJARO x64-advanced-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Manjaro Linux (Kernel: 5.8.18-1-MANJARO x64 - fallback initramfs)’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-5.8.18-1-MANJARO x64-fallback-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Manjaro Linux (Kernel: 5.4.74-1-MANJARO x64)’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-5.4.74-1-MANJARO x64-advanced-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Manjaro Linux (Kernel: 5.4.74-1-MANJARO x64 - fallback initramfs)’ --class manjaro --class gnu-linux --class gnu --class os $menuentry_id_option ‘gnulinux-5.4.74-1-MANJARO x64-fallback-b44ae177-66c6-4f6d-b820-ada2bdf8bfdd’ {
menuentry ‘Windows Boot Manager (on /dev/nvme0n1p1)’ --class windows --class os $menuentry_id_option ‘osprober-efi-1BA4-CFA9’ {
menuentry ‘Pearl 7.1 Rolltide LTS (7.1) (on /dev/nvme0n1p4)’ --class pearl --class gnu-linux --class gnu --class os $menuentry_id_option ‘osprober-gnulinux-simple-67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
submenu ‘Advanced options for Pearl 7.1 Rolltide LTS (7.1) (on /dev/nvme0n1p4)’ $menuentry_id_option ‘osprober-gnulinux-advanced-67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
menuentry ‘Pearl Linux 7 PDE (on /dev/nvme0n1p4)’ --class gnu-linux --class gnu --class os $menuentry_id_option ‘osprober-gnulinux-/boot/vmlinuz-5.4.0-42-generic–67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
menuentry ‘Pearl Linux 7 PDE, with Linux 5.4.0-42-generic (on /dev/nvme0n1p4)’ --class gnu-linux --class gnu --class os $menuentry_id_option ‘osprober-gnulinux-/boot/vmlinuz-5.4.0-42-generic–67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
menuentry ‘Pearl Linux 7 PDE, with Linux 5.4.0-42-generic (recovery mode) (on /dev/nvme0n1p4)’ --class gnu-linux --class gnu --class os $menuentry_id_option ‘osprober-gnulinux-/boot/vmlinuz-5.4.0-42-generic–67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
menuentry ‘Pearl Linux 7 PDE, with Linux 5.3.0-19-generic (on /dev/nvme0n1p4)’ --class gnu-linux --class gnu --class os $menuentry_id_option ‘osprober-gnulinux-/boot/vmlinuz-5.3.0-19-generic–67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
menuentry ‘Pearl Linux 7 PDE, with Linux 5.3.0-19-generic (recovery mode) (on /dev/nvme0n1p4)’ --class gnu-linux --class gnu --class os $menuentry_id_option ‘osprober-gnulinux-/boot/vmlinuz-5.3.0-19-generic–67fd5b92-ef74-402f-848b-b0c9a6e44fc3’ {
menuentry ‘UEFI Firmware Settings’ $menuentry_id_option ‘uefi-firmware’ {
menuentry ‘Remix OS’ --class android-x86 {
menuentry “Memory Tester (memtest86+)” --class memtest86 --class gnu --class tool {

This might not be any problem, I just wonder where they came from since they all are occupying the same partition. My guess is that something must be wrong with os-prober, but I have no proof yet.