I toggle editing on a layer, open the attribute table -> Field Calculator -> Check 'Update Existing Field' -> Select 'myfield' in dropdown -> type...
myfield / 60
-> Hit 'Ok' -> Save Edits -> Stop Editing
The changes seem to appear in the attribute table, but when I close the attribute table and re-open, the changes are gone. When I export the result to geojson, the changes aren't there either.
Any ideas on how to persist these edits short of making a new field? This is on QGIS 3.4 Madeira, Windows 10.
EDIT: I cannot even persist changes in a new field: the result is all null