I observed the following last night:
- A follows B on Attackpoint as a favorite
- B updates his log and thus appears on A's favorites list
- A reads the update to B's log and B is removed from A's favorites list
- B adds a note to his log that comprises a private note and nothing else
- B's log reappears in A's favorites list
I haven't tested this, but I'd guess the same thing might happen when the only update to an existing entry (whether a training entry or a note) is to add a private note.
I don't know how much effort would be involved in conditioning inclusion in the favorites lists on whether there's been a change to the 'public fields'. But I figure it could be a neat little enhancement to make.