Today I was trying to make a Ferz-non-consecutive killer sudoku puzzle, and I ran into this issue that I believe to be a bug with the solver.
This is the grid state before the step:
https://i.imgur.com/uZwXLL2.pngAnd here is the grid after:
https://i.imgur.com/vVTzrEt.pngI believe this step is invalid because it eliminates candidates that appear in the following solution grid:
https://i.imgur.com/rdeMQuI.pngNo candidates from this solution grid were eliminated prior to this step, and this step should not assume uniqueness to my knowledge. This leads me to believe that the candidates were eliminated in error.
This is the starting grid I used to attain this solver state.
https://i.imgur.com/ZRY52MC.pngI linked these images as urls because they appeared quite large on the preview.