What is causing texts from my Galaxy S5 showing up as blank screen on my wife's Galaxy S6?

[AC Question]

It does not happen with each text, but happens quite a bit. What do we need to do to resolve this issue?

 

[B. Diddy]

Welcome to Android Central! Are these simple texts (SMS), or picture texts (MMS)? Did you used to have an iPhone, and if so, did you completely deactivate your iMessage account?