Gets stuck in wrong transition direction

[foucist]

I was playing with the example, in desktop safari. I noticed a bug:

First of all, incognito mode, safari 11.02:

Click page 'next' until it loops back to page 1
click [disable]
Click page 'next' until it loops back to page 1
click [enable]
Click page 'next' until it loops back to page 1

Then hit browser back button a bunch of times. It initially does the correct 'left-to-right' transition, but then at some point the transitions get flipped.

Then if you start going forward again, it uses the opposite/wrong transition also.