I think that living in a country where 10% of the area is covered by lakes is helpful. Our second largest lake (Päijänne) had also dried up some times ago, when a user modified the shoreline. It took a while to restore the lake, since the shoreline is more than 2000 km (almost 1400 miles) long.
I checked the riverbank relation of Hawkesbury River with OSM Relation Analyzer, even though it’s not the best tool for these kinds of relations. But there’s a map tool withing the checker. “Hot air balloons” show where there might be a problem with the relation. I found an “extra” balloon and could therefore fix the relation easily.