I think this can happen if there is a significant schema change in a table. Basically, the backup file indicates that the BLOB column is one type (say, an TEXT) and then you change the column to another (say, NTEXT). Log Rescue will then try to retrieve this column as TEXT when it is not.
I don't see any workaround for this. We will definitely look into making Log Rescue more happy about schema changes. If you start with a more recent full backup and compare some more recent logs, I'd imagine that Log Rescue would work just fine.