Fixerman - Nice phrase ...... "set down upon the water inadvertently"!!
I hardly think it hindered the EC225 rescue ..... it "alighted" pretty close to the rig (500m) and witnesses raised the alarm. But yes there was an issue with the passenger PLB's and interference with other supposedly smart ELT's ..... I think now software resolved.
The issue here is though in remote areas, without airborne SAR, a SART is far more likely to effect a faster rescue as all international shipping nearby will receive it - not someone miles away searching for the HEX code, owner's contact details. Personal PLB's are really only for close in, I would suggest, once the SAR aircraft arrives though modern ac have thermal pictures etc.