Yes, this is expected.
Your picture is not showing a “fallback menu” but the regular grub menu. And this menu shows all installed kernels. In your case 5.8 and 5.7. And for each kernel you see two entries. The entry with “fallback initramfs” in the name means that this kernel starts with a more failsafe initramfs. Just in case you mess up your initramfs with mkinitcpio, the “failsafe” kernel might be your rescue.
Just a few words / recommendations regarding this topic:
Kernel 5.7 is basically end of live. Very soon you will not receive any updates to this kernel anymore. This makes it a bad choice as a kernel to keep installed. You should rather think of installing kernel 5.4 which is a log term support kernel. Just in case kernel 5.8 breaks for you, the LTS kernel is a good fallback solution.