"A pity all German war diaries aren't available. "
Yes, that´s sad. Neither the triple-volume "Sachsen in großer Zeit" nor the Reichsarchiv #9 do mention the 24.Inf.Div. in the period of that battle.
That´s why I assume, the 139 was NOT engaged in the battles around Loos. Please have a look at at map from sep,25.
We see Inf.Rgt.179. 139 was north of them outside the map. Probably they had enemy-contact, but not in a major battle. (I don´t know exactly, where they were in october)
Here I have another map. It shows the situation at the beginning of the battle