Does the Indivision ECS have analogue and digital output? I know on the AGA model it can be toggled; I'm wondering if your Indivision may be set to digital, or if set to analgoue+digital if the digital 'noise' is effecting the analogue sync signals (there is some crosstalk/interference on the AGA model). Perhaps the Picasso is particularly fussy?
Of course, this may all be irrelevant for the ECS model...