This fixed my Bionic so the 4G stays BLUE!

Home>Settings>Battery & Data manager>Data Saver> Turn it OFF

Home>Settings>Battery & Data manager>Data Delivery> Turn ON Background Data AND Data enabled.

Go back to home. Power down your phone (Turn it off) .

Wait a minute then Power back on.

Since I've done this almost 24 hours ago I haven't lost the 4G LTE connection once. It stays BLUE.

Hope this helps all of you.