General :: Lose Root Permissions Each Time

Every few days(sometimes once a day) I get a 'new' android 4.3 update, which once it reboots into the teamwin bootloader, and finishes installing the update(which always seems to work for first 2 steps but says no contents in file, then 2 errors after) I lose root access and it asks if I want to reapply (which I do) and it loads as normal on a restart. I am with build number JWR66N now, but the info page on the TWRP window shows it updates JWR66N to (And I forgot the number here, but its different)

So I'd like to know, is it normal to have 'constant' android updates like this, and if not, what build number should I have?

I have had this issue since about a week after I got my nexus, its been rooted ever since, but in an attempt to fix this issue(Which is just annoying, I doubt its causing any real damage) I unrooted the nexus, updated it(Manually) and re-rooted it using the wugfresh rootkit.