This app was mentioned in 3 comments, with an average of 2.00 upvotes
What are you talking about, the suggestion (ad) in the background lock screen? it was added a few months, it is content from your Blinkfeed.
https://play.google.com/store/apps/details?id=com.htc.lockscreen
Yup. The phone rebooted itself after the Sprint OTA update, then I rebooted it when I noticed the lock screen reverted back to the old one (but rebooting didn't do anything).
So I just reinstalled the HTC Lock Screen via the Play Store, rebooted as part of the install, and it's been working fine since.
I wonder if any other part of the Sprint OTA update was rolled back like the lock screen was. It was 310MB IIRC.