Your comments

So, I've just experienced the issue again, It actually does not save the last topic viewed if ANY other tab (not just topics in new tabs) is opened or you are inactive for a while and was logged out. It will be nice if one could just navigate to the last topic if the auto save doesn't work. I've had to start from the beginning again after I've almost completed 40% of the course

Yes it was because I had another tab opened. Working as expected now. Thanks