Changing to different Slide Master

Hi John, 

Thanks for reaching out!

I can confirm that I was able to observe the same thing happening on my end. I tried a few troubleshooting steps, such as recreating the text box, but it appears that the 'Slide Text' text boxes in the first slide master is not recognized by the second slide master and vice versa. 

I opened a support case on your behalf so we can have our support engineers take a closer look at the behavior. Someone from our team will be reaching out shortly to help investigate the behavior!