A new disease - bacterial canker?

My RT x GDZ F1 plant in 5 gal bucket seemed to have a unique disease/condition not seen in any of the other plants.    Browning of leaf margins ("marginal scorch"), mainly, on older leaves at the end of branches, and without profound wilting.  This is different than the wilt I've often seen in my garden bed tomatoes.  The leaf appearance matches images of what is most often called "bacterial canker" via online research. 

I isolated the pot from the other plants and around June 15 I trimmed off all of the affected branches, using an old scissors I was discarding anyway so as not to contaminate other plants.   Here are before and after photos.