I downloaded QGIS 3.4.0 and try to save edits in .geojson file. I can save new objects, but not edits in attributes. Insted of it, QGIS creates .tmp file with my chаnges into the same folder with editing .geojson. To save my edits I had to copy the text of .tmp file and put it by hand in my .geojson. How to enforse QGIS 3.4.0 save changes in layer like it was in 3.2.3 and do not create .tmp files?
UPD: For further validation analysis I use .geojson in classic JSON tree-like structure, but QGIS - in his own structure stroke-by-stroke. And if I export my .geojson by QGIS, it saves the file in his structure and this new one could be edited and saved with no any .tmp files. So it looks like QGIS 3.4 cannot save edits if .geojson file has tree-like structure (unlike QGIS 3.2).
UPD2:Below parts of broken and working GeoJSONs