If a Legend expires at the end of the 1st fight you don’t have the option to select the next Legend (ie. the icon/button is not shown). So you need to exit the fight sequence, go to Fort and activate Legend, then return to start another fight sequence (essentially from 1st fight again in a new streak). Okay, it’s only 1 fight down, but it shouldn’t be a different routine? I don’t know if any other items are not included in this different routine? It should be the same as additional fights in a sequence.
I have noticed this as well, a few times when I have been streaking I forgot to check when the Legend I have selected will expire, and then had to go into the next battle in the streak without a Legend. It would be great if this was fixed