Kendrix: "Rei II" - Initially, the nummeration appears to be just a way to tie both episodes of the mini-arc focussing on the titular girl together, but as we later learn when a "Rei III" pops up, there is a bit more meaning to it...
One could theorize that those first title cards are that way because ep 5 shows us the things a bit of the things all Rei clones have in common/ what her initial state was like, and the next one shows us the beginning of the developement that would make version II so unique, but that might be overanalizing it.