Hitting right arrow key multiple times, until the last tour step, breaks the tour

The tour steps can be navigated using clicks+buttons or keyboard arrows.

Clicking multiple times on the right key, breaks the tour:

• the Backdrop is missing, see expected.png vs. bug.png
• the buttons are not working, not being able to: go prev step, end the tour or clicking on the close button

I noticed that this mostly happens for the last step in the tour.
The left arrow key does not have the same problem.