I suspect the patches you have called out were written with a firmware update earlier than 1.31 in place.  Certainly a few patches written with the original public release firmware in place did run close to the wire in terms of DSP resources.  There were a couple of minor issues with the DSP usage and limits in the first release with the DSP limit being able to be fooled into working when it shouldn't have by turning off cab emulation to get a patch to load and then turning cab simulation back on.  The limits were tweaked a little to overcome this.  I'm not aware of any other tweaks like this in later firmware releases but there may have been some.  The answer to your question as to why these patches won't load is in my opinion prbably because they were written with older firmware in place.  All you can right now do is to load the patches in edit and tweak them by replacing a a DSP 'expensive' effect or amp model with something a little less demanding.  Maybe you could PM the original authors of the Custom Tone tones and let them know that these patches no longer load and maybe they might be able to re-do the patches in such a way as they will work.

No - I don't think your unit is defective.

Regards

Nick