I've recently started the ODST campaign again with the goal of finding the logs. (The reason I did campaign and not replay is so that I can also get Good Samaritan)
I've looked up a map of all the logs, but sometimes when I go to that location the log is not "active". A little while later I come back and it is. I've tried searching for them in order according to a map, but the logs are rarely available at the time I find them even when I follow the map's numbering.
Does anyone know why this is? Does it have anything to do with the fact that I'm playing campaign, and not replaying Mombasa Streets?