Our unit has 2 hikes on the same day. The 1st hike attendees are a subset of the 2nd hike attendees. I enter Hike #1, no problem. I enter Hike #2, but a hiking log entry is only recorded for those (Cub) Scouts who did not go on Hike #1. I select a random Scout (my son) and enter Hike #2 manually, no problem. So the bug has something to do with Quick Entry. I suspect the same bug shows up with Camping Log, Service Log, etc (untested).
Gary, which path are you taking to add these log entries? Are you using Quick Entry from the calendar? If so, it is part of the Feature Assistant Extension.
I am using the path SB -> My Dashboard -> My Unit -> Quick Entry -> Enter Hiking Log. I am not using SB Feature Extension (for this particular feature).
I hope this helps,