I downloaded Hyrcan t test it out today and I tried a random file (script attached). I tried a few things that may have to do with it but here is the gist:
* I first made a slope under just over 30 degrees with a material of 30 degrees and got a reasonable result (abut 0.98)
* I then added a very weak layer with only 5kPa cohesion (the program does not seem to support undrained behavior, but since I don't have a piezometric line the total stresses should equal the effective stresses) and got a failre, which I expected
* Finally, I added all the other calculation methods and retried. To my surprise, the FoS is 0.000 in Spencer ad GLE, 0.001 for Janbu and the same as it was for Bishop.
* I tried the same geometry in Slide2 and got FoS values in the order of 0.3ish across the board, so there might be someting ging on.