systemd mounts /proc, /sys, /dev/shm, /dev/pts and a few other virtual API file systems in C code during early boot. There's no need to list them in fstab. In a systemd world fstab is for real file systems only.

It doesn't really hurt listing them, but things will be a bit slower than necessary if you do, since we try to remount to apply the configured options, even though that is usually a NOP.

So, yeah. It's not a biggie, no priority, but in the long run those virtual dirs should not be placed in fstab anymore.