Guest dog is aggressive towards my dog

I started watching someone’s dog(H), in my home, two days a week. She is a French bull dog and about 10lb (and as many inches) smaller than my dog(B). H is generally a chill pup, but has shown some aggression towards B. At first I thought it was just a “you are being too much, knock it off” to B, because B is very high energy(jumpy terrier/supermutt). Just now though, I was petting H and my dog (calmly) walked over to me, so I turned and pet B. H was upset by this and went after B, she quickly backed off when I (kinda yelled) “hey”, and my finger did get caught in the cross fire(tiny bandaid needed).

What would you do? Would you continue to work with H, give it time? Bring it up with the owner? My inclination is that she will adjust with time and I want to give her a couple weeks. This may be a bad idea though, and I tend to give animals all the chances and sometimes I need to set boundaries.