It seems that all of them are from the battles of Lwów and around Lwów - all of them were suffered on 12th of September and later.
It is very, very strange - because this division fought several major battles before 12th of September (at least 6 - as can be seen in the map below) - here is a map of its battle-road:
I really don't know a battle in history without a single casualty - maybe these were first - but I would rather say that authors you quoted are mistaken, and losses given above are only from the battle of Lwów (and nearbyhood), suffered since 12th of Septmeber - and not casualties from the whole campaign, with period before 12th of September included.
German daily reports from Christoph Avender's ww2 day by day confirm it - they say these are only casualties from the battle of Lwów.
It seems - that at least 7 - because this one - fought on 10th of September - is not marked in the map above:because this division fought several major battles before 12th of September (at least 6 - as can be seen in the map below)
In the morning the enemy tries to destroy the german bridgehead but is rejected. Polish resistance on a height at Zagorz is broken with artillery support and the division starts to pursue the enemy. Polish resistance again at 2km behind Liska. The defended bridge there is taken after short fire fight. Olszanica is taken against enemy resistance. In the evening the enemy attacks the advance column surprisingly. One 2cm is destroyed and the enemy opens fire from all sides. During the night the village is secured and cleaned.