No, it works fine as far as I can see. It's just that the count doesn't start at zero but at -256 (if interpreted as a 2's complement number) and than all the Fs are changed to 0s when it goes from negative to positive. I guess asterick made it that way to show that the caries work (or else you would have to wait an eternity to see them all change).
It only takes approx 256 tics. This is the point where the first two crates reach F (16 digits for the second crate, or 256 if the first 16 cycle 16 times) , "carrying" the next digit all the way down the line.
Here's an even larger one with 80 digits and a faster carrying between rows. It's based on the same mechanism, but the removal of all the furnaces except for the last one allowed me to collapse three rows at the top of each layer into a single row. rybicol.