You are describing what undefined behavior might manifest in response to a bit flip. It is undefined for the reason that anything can go wrong, although I have trouble seeing how the particular scenario you describe here would cause a problem. If the checksum verification fails on a read because of a bit flip in the data, ZFS will just load another copy.

That being said, it is not a good idea to use hardware that lacks ECC RAM. No filesystem developer will claim that their kernel driver can operate properly without ECC RAM because it is not possible. Email the linux-fsdevel mailing list if you want confirmation.