Coptic texts, such as in the "Gospel of Thomas (Coptic)" logosres:gspthomcop;art=title appear as boxes in the Android app.
If it was windows I would say it was a font issue. Maybe it's the same?
I can reproduce this, I'll write up a case. Thanks for the report!
This will be fixed in the next update. A new coptic font was added to the apps.
Thanks, Gabe and Drew!