Update: This only seems to be occurring in Grid View. List View is functioning as expected.

Hi John , 

Welcome to the Box Community, I'm happy to help!

I'm really sorry for this inconvenience. To assist on looking into this, I've gone ahead and created a ticket for you so that an agent can work directly with you on this issue. 

Kindly check your email for details and updates.

All the Best, 

I do not have an option to select multiple files in the box app.