this might be a case where the licensing on an observation and/or the licensing on the photos may not be permissive enough to allow them to be pushed over to ALA.
it’s possible there may be other problems, too, though. it sounds like there a few things that may need to be worked out in the interface between iNaturalist and ALA. see https://forum.inaturalist.org/t/problems-with-sightings-being-transferred-to-the-atlas-of-living-australia/14466.
if you can provide a few examples of problem observations, it might be easier to provide a more definitive explanation of what might be going on.
some more details about the data issues or examples might help us help you a little better.