Unless you are willing to fix this bug in predictable time, I am a developer now:
convert: unable to open image `+1570': /usr▒²©Ú64/Image`²©Úÿ @ error/blob.c/OpenBlob/2489.
convert: unable to open image `SAD': /usr▒²©Ú64/Image`²©Úÿ @ error/blob.c/OpenBlob/2489.
(the message emitted should make sense)
I am going to fix the warnings first, because last time I spent two days debugging it was because I ignored the warnings. And it is better to fix the warnings once and for all than to have to sift through them each time in hope of finding something relevant. Also, I am actually unable to debug the library code because it is intensively optimised (which is a good thing, of course).