In RFC-0313, validator node registration binds a locked UTXO to a validator node public key through the use of a Schnorr signature, with the intent that the node operator signals its willingness to participate as a validator node.
Because this signature only binds the UTXO commitment and not an epoch, block producers can influence if and when the registration takes effect, as long as the registration transaction remains valid. It should be asserted that this is intended behavior.