July 2015 OTA update concern.

I have (or had) an AT&T branded S5 that was previous rooted and running Safestrap (I don't recall the BL version). Due to some EXTREME idiocy on my part, I took an OTA update two days ago, which updated and synched everything to G900AUCU2ANG3.

Naturally, this borked root. But there's some weirdness going on. Even after the OTA update, the phone's device status still says "Custom". And I still see the custom text when the phone boots. Is this Knox related?

Further oddness is that the phone keeps trying to pull down a second OTA update that looks identical to the first based on the filesize (over 400 MB). It goes through the motion, boots into recovery, and starts installing this second update, but stops partway through. Upon rebooting, the phone tells me the update was interrupted and can't be installed.

I realize I may never get root back, but I'm alarmed the phone's status still says "Custom" and that it's trying (and failing) to install this second OTA update.

I've tried factory resetting the phone, both within KitKat and via recovery, but these issues remain. Should I just reapply NG3 via Odin?

Thanks in advance!