Hi Ruud,
after installing the Version 4.0.0RC1 of ochResponsiveImages, I noticed all Images are delivered with loading="eager", even though the configuration is set to "Add Lazy Loading attribute: yes" and "Add Eager Loading attribute: 1". The debug mode confirms the image number is calculated correctly (given the debug-image-number attribute), so this might help narrow down the bug. Version 3.0.0 works as expected.
Cheers,
Markus