Hi Emilio:
It looks like your body text is set to keep 2 lines together—that's why you have two lines at the bottom of page 27 and two at the top of 28. This is very standard in publishing, and it avoids leaving one line of a multi-line paragraph alone at the top or bottom of a column.
If you don't like it, the options are to
- disable the feature (uncheck Keep lines together) as per Robert so that you have 3 lines on page 27 and 1 on page 28, or
- copy edit—edit a sentence page page 27 so that it wraps to one more line, or
- play with spacing settings to see if you can fix it yourself. For example, you could increase the tracking on that page to ever so slightly widen the character spacing so that one of the paragraphs wraps to a new line.
Note that most of my editors would flag it if I tried the first one, and the second option is considered the right way. I often don't have editing privileges so I will go with three if I'm sure it won't be noticeable.
~Barb