My wife and I each have an SII and I've installed NMS on both phones. On her phone, everything looks and works just fine. My phone has the problem. First, both phones are identical with identical setups.
Occasionally, NMS will tell me I need to upgrade to the full version. I double-click the message and it evidently satisifies itself that I do in fact own the full version. Next, the text and call blocking icons will disappear. Currently, I only have four icons on the first page: Anti-Malware, Anti-Theft, Backup, and Web Protection. The blocking icons are gone.
This doesn't happen on my wife's phone.