The problem is not just from the run of these cars from a few years ago. I purchased a two pack of Lionel Chessie Steam Special heavyweights earlier this year from the latest production run. That's 6 journal boxes per truck times 4 trucks equals 24 journal boxes. I found 6 journal boxes floating around loose in the packaging for a 25% failure rate. Lionel knew of the problem and did nothing to correct it.
I wound up gluing the loose ones back on. So far none of the others have fallen off but expect sooner or later they will.