I have a piece of music that all finished except that I have a problem with the ottava spanner for low a in the bass. It seems to want to span the grace note that's in the next measure, I assume because the grace note is realized by backing up from the beat it's on. My example file isn't "tiny", but it's not huge either. I don't know if people prefer inline files or attachments when they are big, so I attached the file.
I've tried several things to make make the spanner smaller, but I can't seem to do it without messing other things up. There's a lot happening in that measure, including a tied cross-staff chord. There may be a better solution for that that will make the ottava problem easier to solve.
The last measure in the example is how the first measure should look.