I’ve noticed this since I started using Readlang. Finally getting to posting it.
If you select the phrase right after one of the markers that, if you click on it, will generate a summary for the preceding text, then the context includes some stuff from before the phrase you selected, but misses some of it. Here’s an example
Here the word ristorante, plus a period, plus some kind of space, is elided. For me it would be fine if none of the context before the summary marker were there, but if it’s there, I don’t want it to cut some part of, often producing an ungrammatical sentence.