When can I see comments for a segment?

For comments to be visible on segment-level, you need to have at least the same amount of active user, i.e. that are included in the survey sendout, as the minimum segment size in your settings

For example: your minimum segment size setting is 5. If you have 5 or more users within one segment that are active, you will be able to see the comments as soon as one user has left a comment. This applies for survey comments and general comments.