question about facebook chat?

[Manuel]

ive seen this one person with the mobile icon on facebook chat with nothing next to it like for example no 1h or 1m but then for past couple of days ive seen the 1h or 1m next to it an now all of a sudden again all i see is a mobile icon with nothing next to it? i dont get it.

[Maylene Benitez]

Yea but sometimes those aren't actually helping at all. Don't trust what you see at times ._. hmmm