My guess:
This appears to be a bug in the LR 4.4 software, and I guess it is something like this, based on my experience as a C/C++ programmer:
The problem occurs when a complex image is behing handled by the print module. Here I'm assuming that some kind of lossless compression is being used.
It appears that a fixed space is allocated for the image, based on the print size and bit depth. (thus a different bit depth might not work much better, anyway, even if one didn't care about the compromised quality). This space would work for most images, but those beyond a certain threshold of information content would require too much space. In this case, the saved print image would be smaller than the printed size. When the data is sent to the printer, and the end of the saved image is reached, the first 0.5" of the image is sent repeatedly.
An expert on the internet pointed out that the Epson 3880 stores one line at a time.
Another clue: cables of length greater than 10' might cause troubles. Mine is 8', but the longer cable would have a slightly longer transmission time, as well as more chances for picking up interference.
If my first scenario were correct, it would explain why an image with lower information content, thus smaller after lossless compression, would print correctly, but an image that is larger under lossless compression would not.
I'm not sure whether or not this is a good explanation. If it were, the solution would be to perform a check of the validity of the lossless compression. If it were invalid, a message could be provided that the image could not be printed, thus saving expensive paper. Alternatively, a better dynamic allocation of the print image could be used. There might also be issues with timing the output to the printer, but a pause could be made if it were necessary for the computer to catch up with the data flow.
I believe I could solve this problem if I had access to the source code. But that should be Adobe's job.
It does not appear that LR 4.4 software is capable of doing this correctly, or even of delivering an error message when it can't do the job that it is supposed to be able to do.
Adobe, are you listening?!
Frank