I do not know. Both of them are from Phoenix loureiroi x dactylifera batch of seeds I got from you.
Then you are lucky because you most probably have two different crosses, loureiroi x roebelenii and loureiroi x dactylifera!
I see that difference is not restricted only to morphology but the dactylifera hybrid grows faster than the roebelenii one, which qould entirely predictable in such case.