Saeviomagy
Adventurer
This is super stealth errata.
My copy of the OFFLINE Character Builder has no Divine keyword on Healing Word.
I don't know why the change was made, but it probably wasn't because of the Sentinel.
Are you sure it's not just a bug? Was there a specific "hey, we removed the divine keyword from healing word so that X happened"? Because otherwise I'm inclined to believe that it's a software bug - that the character builder is using the wrong healing word, or someone just changed it because it didn't make sense that it was a divine power being used by a primal class or vice versa, and they're not in a position to understand the implications - compounded by someone copy-pasting from the character builder.