Yes, there appears to be a limit on the y dimension that is some number greater than 1047552 but less than 1048576. (The maximum acceptable value for y appears to be (1024x1024)-16) If this is a problem for you, you could file a bug. However within the acceptable range of y, it seems that x can be much larger than 16 or 32, so there doesn’t seem to be a particular limit at 32Mb as indicated in your original posting.
FWIW, I believe x has a larger limit than y, so I believe a transpose of (1572864,128) should be possible, for example.