The CASESTOVARS command occasionally fails to "expand" certain variables in the resulting restructured dataset.

Problem

I'm using IBM SPSS Statistics and have received some puzzling results when restructuring a file with the CASESTOVARS command (Data->Restructure). The original variables to be restructured are occasionally only copied to a single variable in the new file. This has occurred when there is only one valid value across the records within each unique ID value, and also when there is a combination of one valid value and system-missing. For example, I ran the following commands: data list free / Id rec x y . begin data. 11 1 1 2 11 2 . 3 11 4 . 1 12 1 . 4 12 3 . 4 12 4 2 2 12 5 2 3 13 1 . 2 14 1 . 3 end data. execute. formats rec x y (f4). * I then ran CASESTOVARS to restructure the file. Casestovars id=id /index=rec. list. What I expected to see in the LIST output was: Id x1 x2 x3 x4 x5 y1 y2 y3 y4 y5 11 1 . . . . 2 3 . 1 . 12 . . . 1 . 4 . 4 2 3 13 . . . . . 2 . . . . 14 . . . . . 3 . . . . What was actually printed in the LIST output was: Id x y1 y2 y3 y4 y5 11 1 2 3 . 1 . 12 1 4 . 4 2 3 13 . 2 . . . . 14 . 3 . . . . There is only a single X variable in the restructured file, although Y was restructured into Y1 to Y5, as expected. If I rerun the commands, but first recode sysmis to 0 for X and Y before the CASESTOVARS command, then X is also restructured into X1 to X5. It appears that the combination of a single valid value plus system-missing values within each ID is treated as a within-ID constant by CASESTOVARS. Is this interpretation correct? Is the treatment of system-missing values by CASESTOVARS explained in IBM SPSS Statistics documentation? Is there a workaround to force a variable such as X in this example to be restructured into a set of variables as determined by the value of the record variable?