Sorry to jump in here, but I am having an issue and been trying on my own for some time to resolve...
With an install of the new Moodle, and latest of AL, all looks well and seems to perform as it should. I mean it goes through all the correct steps and allows me to lock lock the previous lesson, however my students can still see ahead. The locks are there, and a mouse over showes what is needed to proceed, however nothing is greyed out, and they can click through the lock...
I have tried the uninstall, and read through this post, following along with other suggestions, and still no further ahead...
Any advice???