Hi @rseilham ,
Glad you asked. When a day had gone by and no one responded here, I put in a ticket, and got a good answer:
The lock signifies that final grades in the course site are hidden from students. We have that as our default setting. The N/A signifies that there are no grades or graded assignments in the site (I think I have that right - or maybe that there are some things waiting to be graded, though that makes less sense).
I find it surprising that these exist in the Android version of Student App 6.4, but not in the corresponding iOS version. Since I think that the significance of the icon is not intuitive, I would say that making the Android version conform to the iOS version would be the way to go. Nonetheless, I'm relieved to know what the Android app is trying to tell me.
This is how it looks.

Best,
-Peter
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Peter Hess
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