I was watching the Biblical Hebrew Course and I needed to go back to review a previous lesson. The channel would not allow that to happen and continued to play only the current lesson. Wondrium acknowledged that some of the courses do that, but offered no solution -- said they were "working on it."
This is what worked for me...
1. Get to a computer or other device and use the online version of Wondrium to clear out your history (under your Account)
2. On the main Roku settings, make sure that you have unchecked continuous play of lessons. It says something to the effect of "automatically proceed to next lesson." Make sure that option is UNchecked. Try again to replay the older lectures.
3. A restart is always helpful, I suppose. If you uninstall Wondrium and reinstall (I did not do this) then you will have to sign in again. ugh
4. This worked for me -- hope it works for you.