The mount command by default has all the filesystem drivers probe the partition until one recognizes it is is its type and mounts it. That error message is just a warning from the f2fs kmod that during the process a f2fs filesystem was not found. Which is expected behavior if the partition is formatted with a different filesystem. The other drivers silently ignore finding a different filesystem.
If you aren't going to be using any f2fs partitions at all, you could remove kmod-fs-f2fs. Note that the squashfs images for x86, Raspberry Pi, and a few other platforms use f2fs as the overlay, so f2fs must be in the kernel. The optional ext4 image does not use f2fs, but it runs the same kernel with f2fs built into the initial load, so it's going to be there unless you make a custom kernel build.