Thanks for the report. It does seem that a bug has crept in --we are looking into it.
Btw, we have integrated lately an alternative finite domains library 'clpfd' (contributed by Emilio Gallego and others). It is in the system repository but we have noticed that it is not being included in the 1.15 snapshot distros. We will include it shortly. The new stable release that we are working on (1.16) will also include it.