FOTON: Zeros on the imaginary axis are trigging RHP Zero warnings
RHP Zeros warning requires positive real value. Probably the zeros are being nudged from axis by foton before writing them out.
An repeatable example is needed.
ellip("LowPass", 4, 1, 40, 1)
will cause the warning, though the design string only has 0s in the real value for each zero.
Edited by Erik von Reis