Benjamin,
I am not entirely certain what you mean, but I am assuming that when you run a word study, under "DEFINITION" you are not seeing anything?
That is most odd.
My knowledge of the Android app is a bit limited, but I believe the Bible word studies must be run with internet access, they are generated on server side. Since you mention having the lexica downloaded I suspect you are trying to run them offline. If this is the case than the solution is to have online access.
I only currently have Louw & Nida purchased within my logos software.
Ah, I am not seeing Louw Nida in my list either, I do however see: BDAG, EDNT, and others.
I suspect for some reason that LN was turned off in the mobile app. But I am not certain why. It does appear that LN was broken in a past iteration. I am not sure if this is related.
I've tried downloading the book for offline use. It's just gone.
Do you mean you can't open the Louw-Nida Greek-English Lexicon on your device, or that it doesn't appear in Bible Word Study results? Bible Word Study results come from Logos' servers, not your device.