I have a little data to add. It happened to me three separate times over Memorial Day weekend. Twice using the live map, once using an offline list. In all three situations I saved the log rather than sending. No matter what cache I tapped after hitting Done on the log screen the information for the cache I'd just logged came up. The problem was resolved by hitting refresh.in the live map or closing and reopening the app when offline. Again in all three instances, it did not happen for the next cache.
I couldn't replicate it at will either. Hopefully the observations will help.