I also started experiencing this problem a month or two ago (May/June 2012).
I'm on a Motorola Droid 4
Android 2.3.6
System 6.13.219.XT894.Verizon.en.US
Location: Springfield, MO area.
Signal Level: 4 of 5 bars.
Plan: Family Shared 900 with grandfathered Unlimited Data from the Alltel buyout...