Cutting Titles and pasting them after clicking Rename slide.

Hello David,

Happy to assist!

I did a quick test on my end by copying French text and pasting it into the slide titles, and I can confirm that this worked without any issues for me. 

Since pasting text isn't working properly for you, try doing a repair of your Storyline 360 installation to see if this helps. If the issue persists, open a case with our support team here so we can take a closer look at what's happening.